Use ripe tomatoes for this. Not all tomatoes are created equal. When choosing tomatoes, look for tomatoes that are deeply colored and firm, with a little give. If they don’t smell like anything, skip them. They should smell like a tomato — sweet and woody.
1 1/2 pounds tomatoes, chopped
1 medium onion, chopped (about 2/3 cup)
1 to 2 jalapeño or serrano peppers, finely diced (seeds and membranes removed for a milder salsa)
1/2 cup finely chopped fresh cilantro leaves
Juice of 1 lime
Salt to taste
Add the tomatoes, onion, cilantro, diced peppers and lime juice to a bowl. Generously season with salt — start with 1/2 teaspoon and go from there. Set the salsa aside for 30 minutes.
After 30 minutes, stir the salsa — making sure to distribute the juices left at the bottom of the bowl. Taste and adjust with more salt. Store for up to 3 days in an airtight container in the refrigerator.