Combine garlic, onion and jalapeno in a blender or food processor and process until finely chopped. Add tomatoes and blend. Add cilantro, lime juice and oil and continue blending. Transfer salsa to a bowl and season with salt and pepper.
Roasted salsa variation: Place the garlic, onion, jalapeno and tomatoes on a sheet pan and roast for 30 minutes at 400 degrees, then proceed as directed.