Add all ingredients to the bowl of a food processor.: Close your eyes for a second and notice the clean herbal perfume from the cilantro and the sharp citrus from the lime juice as you assemble everything. The tactile act of dropping diced tomatoes , chopped red onion , the measured cumin , peeled garlic , and the jalapeño peppers into the bowl already tells you the salsa will be lively. Make sure your processor bowl is dry enough to avoid unexpected splatters, and confirm the lid is seated properly. A common mistake here is overcrowding the bowl which prevents even chopping, so keep the quantities as listed and work in a single batch.
Pulse about 5-10 times, or just until the ingredients are finely diced, but stop before they're soupy.: Listen to the rhythm as you pulse, short bursts create a satisfying chopped texture with little liquid release, while long runs bruise the tomatoes and produce excess juice. Visually, you want small, distinct pieces, not a puree, and you should still see flecks of cilantro and red onion . The slight crunch and the fresh tomato scent are your cues to stop. Avoid over processing which yields a watery, flat salsa rather than one with character.
Pour contents into a fine mesh strainer to remove excess liquid.: When you pour the mixture into the Fine Mesh Strainer , drizzle away free liquid that would otherwise water down the texture. The sound of the juice collecting below is oddly satisfying, and you will notice the remaining salsa is thicker and more concentrated. Use a spoon to gently press the mixture against the strainer if you want to speed the process, but be cautious not to squeeze through too much pulp. A typical error is skipping this step which leads to soggy chips and a less vibrant mouthfeel.
For best flavor, refrigerate at least 2-3 hours before serving.: Cooling the salsa allows the flavors to marry, smoothing sharp edges and letting the lime juice and salt season the entire batch. The temperature shift also tightens the texture slightly and deepens the aromatics so the scent of cilantro and garlic becomes more integrated. When you open the container after a few hours you will notice a more harmonious smell and a rounder taste. Do not skip this rest if you want depth; serving immediately is fine in a pinch, but the flavor will be less cohesive.
Keeps in the fridge for up to 1 week.: Stored in an airtight container, the salsa will slowly mellow and the heat from the jalapeño peppers may soften over time while the overall profile becomes more unified. Before serving leftovers, give it a quick stir and a small taste to check seasoning, adding a pinch more salt or a squeeze of lime juice if it needs brightening. Be mindful of moisture that can accumulate at the top; drain any excess to maintain the original texture. A common oversight is leaving it uncovered which speeds spoilage, so always seal it properly.