If using wooden skewers, soak the skewers in water for at least 20 minutes and up to 1 hour to prevent them from burning. (You can skip the sticks and use an outdoor grill basket or an indoor grill pan).: The scent of wet wood is subtle, and soaking prevents the skewers from charring too quickly, which helps the shrimp cook evenly. You'll notice the skewers feel heavier when fully saturated, and that extra moisture reduces flare ups as they hit the grill. A common mistake is skipping the soak, which can lead to brittle sticks catching fire, so allow the time. If you choose a grill basket or metal skewers instead, the handling changes slightly, but the goal remains consistent heat for even browning on the shrimp .
For the onions: In a small bowl, combine the onion, juice from 1 1/2 limes, and a large pinch of salt. Toss to combine and let the mixture pickle while you prepare the other ingredients, stirring occasionally.: In a small bowl, combine the onion, juice from 1 1/2 limes, and a large pinch of salt : The liquid from the lime immediately softens the red onion and perfumes it with citrus, reducing pungency while adding tang. As you stir, you will see the onion become slightly translucent, a visual cue that the acids are doing their work. Stir occasionally so every slice gets dressed, and taste after a few minutes to adjust the pinch of salt . Avoid over-pickling, which can produce an overly soft texture; for a snappy crunch, keep the pickling time moderate.
For the salsa: In another small bowl, combine the peach, avocado, cilantro, 1/4 teaspoon chili powder, and the juice from the remaining lime half. Sprinkle generously with salt and toss to combine. Make sure it's well-seasoned, then set aside.: In another small bowl, combine the peach, avocado, cilantro, 1/4 teaspoon chili powder, and the juice from the remaining lime half : When you mix these, the peach juice will coat the diced pieces, and the aroma of fresh cilantro will open up. The small amount of chili powder deepens the fruit's sweetness without making it spicy. I often check seasoning at this stage, adding a little salt to brighten flavors. A common error is overmixing, which can mash the avocado ; gently fold to maintain distinct pieces for texture.
Preheat the grill, a grill basket or a grill pan to medium-high heat and spray with oil.: The moment the grill reaches medium high, you should hear a steady hiss when you spray and place food, signaling the surface is hot enough to sear. This quick sizzle locks in juices and creates slight char on the shrimp and corn tortillas . If the surface is too cool, food will steam rather than sear, so patience here rewards you with better texture and flavor. Be cautious with oil spray around open flames to prevent flare ups.
Pat the shrimp dry and spray with oil. Season with 1 teaspoon tajin, 1/4 teaspoon kosher salt and cayenne pepper. Thread the shrimp onto doubled skewers (if using), leaving enough room to hold onto the end to flip them.: Drying the shrimp with paper towels removes excess moisture so they brown instead of steam. After spraying with a light mist of olive oil , the surface will glisten, helping spices adhere and promoting an audible sizzle when the shrimp hit the grill. A frequent slip is skipping the drying step, which can result in soggy, unevenly cooked shrimp , so take that extra minute.
Add the shrimp to the prepared grill and grill for 2 to 3 minutes per side, until the shrimp are pink and firm. Transfer the shrimp to a plate to cool while you char the tortillas on the grill, about 1 minute per side until slightly charred.: These seasonings form a flavorful crust when exposed to heat. The aroma of the tajin and the warmth from the cayenne pepper bloom as they contact the hot surface, creating a fragrant steam. Lightly press the spices onto the shrimp so they adhere, and resist the urge to overload with salt which can draw out moisture and dry the shrimp .
To assemble, remove the shrimp from the skewers and divide equally among the tortillas. Top with a heaping spoonful of salsa, a few pickled onions, and serve, with lime wedges and extra pickled onions on the side.: Threading properly helps the shrimp cook evenly and stay flat so heat distributes across the surface. You will feel the slight resistance as the shrimp pierce the skewer, and arranging them with some space allows hot air to circulate. A typical mistake is crowding the skewers, which prolongs cooking and prevents a clean sear, so leave tiny gaps between pieces.
Add the shrimp to the prepared grill and grill for 2 to 3 minutes per side, until the shrimp are pink and firm: As they cook, listen for a steady sizzle and watch for the shrimp to turn opaque with pink accents. When they are done, they will feel springy to the touch and their flesh will flake slightly. Overcooking makes them rubbery, so check early and often. If unsure, remove one and cut into the center to verify it is opaque and cooked through.
Transfer the shrimp to a plate to cool while you char the tortillas on the grill, about 1 minute per side until slightly charred: Letting the shrimp rest briefly keeps them juicy and makes them easier to handle. The corn tortillas will take on a light smoky note as they char, and the edges may bubble slightly, signaling readiness. Keep an eye on them, as they can go from charred to burnt quickly. If a tortilla becomes too crisp, it will crack when folded, so pull them off just before they become stiff.
To assemble, remove the shrimp from the skewers and divide equally among the tortillas: As you assemble, you will notice the contrast between warm, slightly charred corn tortillas and cool, juicy peach salsa. Add a heaping spoonful of salsa and a few pickled red onion slices to each, then serve with lime wedges. One common misstep is assembling too early, which warms the salsa and makes it lose texture, so wait until the moment of serving for the best sensory impact.