Pour both cans of tomatoes into a colander over a small bowl; drain, reserving 1/3 cup liquid. Discard remaining liquid or save for another use.
In a large skillet, saute onion in oil until tender. Add garlic; cook 1 minute longer. Stir in cream cheese until melted. Add the tomatoes, process cheese, chili powder and reserved liquid. Cook and stir over low heat until cheese is melted. Stir in cilantro.
Keep warm; serve with tortilla chips. Yield: 3 cups.