Peel thorns from cactus pads with a vegetable peeler, leaving the green skin; cut cactus pads into thin strips.
Heat the oil in a large nonstick skillet over medium high heat. Add the cactus and garlic, saute 7-8 minutes or until cactus is tender. Combine the cactus mixture, beans and the next 7 ingredients(beans through tomatoes).
Arrange 1 1/2 cups lettuce on each of 4 plates, top each with 1/2 cup cactus mixture, 1 1/2 tbls. cheese, and about 2 teaspoons sour cream. Enjoy!