Add the diced tomatoes (with their juice), jalapenos, lime juice, salt, and cumin to a blender or food processor.

Pulse gently in short bursts until the mixture is mostly pureed but still has a little texture left - you're not making tomato juice, so stop as soon as it looks right. It's easy to over-blend this, so go slow and check often.

Pour the blended mixture into a bowl and stir in the raw diced onion by hand. Do not blend the onion in with the rest of the mixture - pulsing it into the blender will make the whole batch taste like raw onion instead of salsa.

If you're using the cilantro, stir it in now. It adds a nice fresh note, though it will pull the flavor a bit away from the classic Chili's taste.

Transfer the salsa to a tupperware or mason jar with a tight-fitting lid and refrigerate for at least 4 hours. Overnight is even better - the extra time lets the flavors fully come together.

Serve cold with tortilla chips.