Dice the red onion.If using the jalapeno, cut in half and scrape the seeds and membranes out. Dice the jalapeno pepper.Slice the avocados in half and remove the pits.
Use a spoon to scoop out the insides from the skins and place them in a bowl. Discard the skins.Sprinkle in the lime juice and lemon juice to keep it from getting brown.
Add the canned diced tomatoes with green chile peppers, diced red onions, diced jalapeno peppers (if using), jarred minced garlic, salt, and black pepper to the bowl.