In a large skillet over medium-high heat add oil, cook the onion and bell pepper for 5 minutes or until they look translucent. Add the black beans, the corn, the spices and continue cooking for another 5 minutes. Add the tomatoes at the last moment, and remove from heat.
Place in the oven and cook for 10 minutes or until the cheese is completely melted. During that time chop the iceberg lettuce. Remove from the oven, top with salsa, iceberg, and sour cream. Serve immediately.