1/2 cup black beans, 1/4 cup diced tomatoes, 1/4 cup diced onions, 1/2 tsp cumin, 1/2 tsp chili powder, 1/4 tsp garlic powder, Salt and pepper to taste, 2 small corn tortillas, 1/4 cup shredded lettuce, 2 tbsp chopped cilantro, 2 tbsp sour cream, Lime wedges for serving