Heat 3 tablespoons of olive oil in large hot skillet. Sauté garlic, shallot, corn and cumin over medium-high heat for 10 minutes or until corn begins to brown. Set aside until room temperature. When corn mixture has cooled, place in bowl. Add black beans, red bell pepper, mango, 3 tablespoons olive oil, cilantro, lime juice, salt and pepper. Slice two avocados in half, lengthwise. Remove pit and score avocado meat one way then the other to create squares. Carefully remove squares from shell, keeping shell intact. Add avocado meat to bowl of corn ingredients and gently stir. Fill halved avocado shells with mixture. Top with Cotiga or Feta cheese if desired. Garnish with green leaf lettuce and cilantro. Yields 4 servings. There will be leftover filling for seconds!