Combine cilantro, onion, garlic, and jalapeno in blender or food processor. Process until all of the veggies are chopped, about 30 seconds.
Add the whole undrained tomatoes, sugar, salt, cumin, and lime juice and pulse a few time until you get the salsa consistency that you like (10-15 pulses).
Add the diced tomatoes and pulse one or two times to combine. Test the seasonings on a tortilla chip and adjust accordingly.
The salsa is much better when it has time to sit. Let it rest for at least an hour before serving with warm tortilla chips or any other Mexican dish.
Video
Notes
This recipe is very flexible, add other peppers if you like it more spicy or less spice and adjust everything to taste.