Dice the tomatoes, chop onions and cilantro, stem, seed and chop your jalapeños.
In a food processor, combine onion, garlic, jalapeños, cilantro, lemon juice and all seasonings. Mix the vegetables.
Add diced tomatoes to the food processor and blend a bit more, but do not overmix. I recommend not over-blending homemade salsa, or it will get too saucy.
Adjust with salt to taste, then transfer to an airtight food container or mason jar and refrigerate. Let homemade salsa chill for at least 2 hours or overnight before serving.