Start by putting the tomatoes into the food processor and pulsing until chopped. You don't want to liquefy them.
Pour tomatoes into a bowl.
Pull out any large chunks and cut them up to your desired size.
Put the rest of the vegetables in the food processor and pulse until chopped to desired size.
Mix them with the tomatoes in the bowl.
Add the cumin and mix well.
Add cilantro, if using, and mix well.
Use salt and mix well.
Use a funnel to pour salsa into jars.
Add fermenting weights into the jars to push the solids well beneath the liquid line, and make sure you keep about 1/2 inch free at the top.
Add airlock lids (if using) and allow to sit at room temperature for three days.
Let salsa sit for three days, then give it a taste test to see if it's to your desired flavor. Continue to ferment until it's to your liking, transfer to cold storage.
You can keep your salsa in cold storage – a refrigerator or a root cellar/basement if kept at 50 degrees or less. For long-term storage, the upper 30s and 40s work best. It will last for months and even up to a year and a half in the fridge.