Preheat the oven to BROIL. Preheat the meatballs according to package directions.
In a muffin pan (2 pans of 12, or 1 pan of 20 or 24), place a cooked meatball. Place a chunk of cheese on top. Broil for 2-3 minutes until cheese is melted.
Tear small pieces of romaine lettuce; and cut the avocados and cheese into large chunks.
With a small skewer, add one meatball with melted cheese, a tomato, a chunk of avocado, and a piece of Romaine lettuce folded over.