Coarsely chop tomatoes; set aside. Combine tomato, oil and onion in a large frying pan. Stir often over medium high heat until onion is limp, about 5 minutes. Add tomatoes and peppers; stir often until hot. Add beans and minced cilantro; stir gently until beans are hot. Pour into a bowl. Add juice from lime wedges and sour cream to taste. Serves 4 to 6.