Preheat oven to 400°F (200°C). Arrange meatballs in single layer on parchment paper-lined baking sheet. Bake 15 to 20 min., until browned and heated through. Remove from oven. On each skewer, thread a meatball, piece of cheese, piece of bacon, pickle slice, and a tomato half. Make 24 meatball poppers. Serve with ketchup and mustard for dipping.
Add piece of lettuce or basil leaf to skewer.
Place poppers under broiler to melt cheese.