Prep First. To start, make sure to halve or quarter the tomatoes, dice the onion, mince the jalapeño, and mince the garlic. This will help reduce the amount of blending you need to do, which will cut down on how much foaming happens when mixing.
Combine. In a food processor, combine tomatoes, onion, cilantro, jalapeño, garlic, lime juice, and salt. (Add pinch cumin or chipotle chili powder, if desired.)
Pulse on low speed a few times until your salsa reaches your desired consistency. (Try not to use high speeds--just pulse to blend a bit at a time)
Taste & Adjust. Then, taste the salsa and add additional lime juice, salt, jalapeño, or seasonings, to taste. Keep in mind that the flavor will continue to develop with time!)
Serve & Store. If possible, chill 1-2 hours to let the flavor develop, then enjoy right away with tortilla chips, on tacos, with chicken, burritos, nachos and more, or store in an airtight container in the fridge 4-5 days. (I do not recommend freezing this salsa, since it can get mushy and watery after thawing.)