1 yellow onion, chopped
2 green peppers, chopped
1/2 clove garlic, chopped
1/2 bunch cilantro, coarsely chopped
4 (14-ounce) cans diced tomatoes
1 cup chopped spinach. or to taste (optional; doesn't change the flavor)
Add all ingredients to a blender; pulse blend until well blended, but not smooth. Use as a dip for tortilla chips.