Bring a large saucepan of water to boil. Briefly place 6 pounds tomatoes into water to loosen skins and set color. Drain, peel and crush.
Mix chopped tomatoes, garlic powder, lemon juice, salt, cayenne pepper and cumin into the saucepan with crushed tomatoes. Whip to desired thickness. Bring to a boil. Mix in red onion, white onion, yellow onion, jalapeno peppers and cilantro. Continue boiling until vegetables are soft and mixture has reached desired consistency. Remove from heat. Refrigerate until serving.