Preheat oven to 350 degrees F. Arrange the peppers in a 9 x 13-inch baking dish so that the cavity side is facing up. In a large mixing bowl, stir together the cooked black bean crumbles, cooked quinoa, 1 1/2 cups shredded cheese and salsa until combined. Spoon the mixture evenly into the cavities of the six bell peppers. Sprinkle the tops with the remaining 1/2 cup shredded cheese. Bake uncovered for about 25-30 minutes, or until the peppers are cooked and soft and the cheese is all melted. Serve immediately, topped with optional toppings if desired.