Finely chop the onion, celery, green bell pepper, and the jalapeno
Combine all ingredients
Cover and refrigerate overnight, or at least several hours. Stir occasionally.
Notes
If your tomato skins are thick, you can peel them by blanching. Boil a pot of water, cut an 'x' into the bottom of each tomato. Place the tomatoes into the boiling water for about 30 seconds and then place them in a bowl of ice water. The skins should slip off easily.