Core and chop tomatoes. Seed and mince pepper. Peel and mince onion. (A sweet onion is best, but an ordinary yellow onion works.) Chop parsley.

Mix everything well in a large bowl. Add vinegar, toss well. (Substitute lime juice for vinegar, if desired.) Add salt, if desired, if it will all be eaten in a few hours.

Let rest an hour or two, to meld flavors.

This keeps well, covered and refrigerated, for about 2 days. If keeping, add salt (if desired) shortly before serving, not earlier.