Preheat the oven to broil. Prepare the meatballs according to the package instructions.
Place the cooked meatballs in a muffin pan. Add a piece of cheese to the top of each meatball. Broil for 2-3 minutes until the cheese is melted.
Tear romaine lettuce into small pieces. Cut the avocado into large pieces.
Thread a meatball, tomato, avocado piece and romaine lettuce onto each of the mini appetizer skewers.
Serve the avocado cheeseburger meatballs with ketchup and mustard. Enjoy!