Rinse the tomatoes, lime, jalapeño and cilantro under running water; dry them and use a clean cutting board and knife. Do not use soap to wash produce.

Remove tomato stem ends and dice 1½ pounds of Roma tomatoes into roughly ¼- to ⅜-inch pieces. Remove only overly watery seed gel if needed, and transfer the diced tomatoes to a clean bowl.

Dice white onion very finely and add ⅓ cup to the tomatoes. Stem and mince a small jalapeño, removing seeds and white membranes for a mild salsa; start by adding half.

Finely chop ⅓ cup of cilantro and squeeze 2 tablespoons of fresh lime juice. Add cilantro and lime to the mixing bowl.

Sprinkle on ½ teaspoon kosher salt. Fold everything together gently, keeping tomato pieces intact; taste before making additional seasoning changes.

Cover and refrigerate for 15 minutes so the tomatoes release a little juice and the flavor develops. Do not leave the finished chopped produce on a warm counter.

Stir gently again, taste and add more minced jalapeño, a pinch of salt or a teaspoon of lime only if needed. Serve in a clean dish. Refrigerate leftovers promptly at 40°F (4°C) or colder.