- Core the tomatoes, then cut in half widthwise and squeeze out the seeds if you wish Finely dice the flesh. Scoop into a bowl. Chop the chiles as finely as you can, then add them to the tomatoes. Carefully bunch up the cilantro sprigs, and, with a sharp knife, slice them 1/16-inch thick, stems and all, working your way down from the leafy end until you run out of leaves. Scoop the chopped cilantro into the tomato mixture along with the garlic.
- Next, finely dice the onion with a knife (a food processor will turn it into a mess), scoop it into a small strainer, then rinse it under cold water. Shake to remove the excess water and add to the tomato mixture. Taste and season with lime juice, cumin and salt, and let stand for the flavors to meld before using.