Place all ingredients--except (optional) diced roma tomatoes--into the blender in the order listed, secure lid and blend until smooth or pulse for a chunky salsa.
For Blendtec: For a chunky salsa, use the PULSE button until it's a consistency you like. For a smooth salsa, use the BATTERS/DIPS button OR manual speed 5 for about 25 seconds.
For Vitamix: For a chunky salsa start on Variable Speed 4 and PULSE** until it's a consistency you like. For a smooth salsa, blend on Variable Speed 1 and increase to Speed 10/High and blend for about 20 seconds.
Add (optional) diced roma tomatoes and gently PULSE 2 times to incorporate.
Can be stored in a closed container for up to two weeks in the fridge or several months in the freezer.