Peel the garlic, peel and rough chop the onion. Slice the jalapeño and discard seeds and membranes if desired. Add all to a food processor.
Process/blend until finely diced.
Cut grape tomatoes in half or rough chop any larger tomatoes. You can chop off some of the cilantro stems if desired. Add both to the food processor with the salt.
Pulse until desired consistency is reached. You can do chunky or smooth! If you really like chunks you can even hold some ingredients back from the processor and stir in at the end.
Add to a half gallon jar or two quart jars. Make sure to leave a decent amount of headspace.
Let rest on counter, loosely covered, for 3-4 days or until the taste is to your liking. Make sure burp the gases!
Move to the fridge when ready to eat, and it will keep for months.
Notes
You can use a pickle pipe if you do a lot of fermentation, or use cheesecloth or a coffee filter with a rubber band.