In a medium bowl, add in the diced tomatoes, white onion, jalapeno, fresh cilantro, lime juice and a pinch of kosher salt. For the best results, let it sit for 10-15 minutes to marinate.: As you combine the ingredients you will notice a burst of color and fresh aromas, especially the citrusy lift from the lime and the sharpness of the chopped onion . Use a medium bowl so the ingredients have room to mingle, and gently toss with a spoon to coat everything evenly. The key sensory cue here is the mingling scent of herbs and citrus, which indicates the flavors are beginning to harmonize. Doing this gently prevents the tomatoes from releasing too much liquid. A common mistake is vigorous stirring which bruises the tomatoes and turns the mixture too runny.
Give it a taste and adjust the salt to your liking. Serve with tortilla chips or top it on your favorite tacos, nachos or enchiladas.: During this rest you will hear nothing but notice the texture change as the salt and lime draw juices from the tomatoes , softening them slightly and melding the flavor profile. The resting period allows the sharpness of the onion to mellow and the herbaceous notes of cilantro to infuse the whole bowl. Visually, you will see a slight sheen of tomato juice at the bottom, which signals readiness. Do not skip this because immediate serving may feel raw and disconnected. A common error is over resting, which can make the mixture watery, so keep within the 10 to 15 minute window.
Give it a taste and adjust the salt to your liking: Once the flavors have had a moment together, sampling is crucial. Use a clean spoon and notice the balance of acidity from the lime , heat from the jalapeño , and sweetness from the tomatoes . If the mixture tastes flat, a little more kosher salt will lift everything. If it is overly sharp, a tiny pinch of salt and another stir will calm it. The sound you should hear is subtle, just the spoon against the bowl, as you evaluate texture. Avoid adding too much salt at once, which is an easy misstep; increment in small amounts and taste each time.
Serve with tortilla chips or top it on your favorite tacos nachos or enchiladas: When serving, note the contrast between the bright, cool salsa and the warm base it accompanies, whether crisp chips or hot tacos. The texture should remain chunky so it provides a fresh counterpoint to fried or rich components. Spoon with care to avoid transferring excess liquid, especially if the accompaniment is meant to stay crisp. A frequent mistake is spooning straight from a watery layer at the bottom, which can sog a chip or taco shell, so lift from the mixed center where solids predominate.