Preheat oven to 400 degrees. Line a baking sheet with foil and lightly coat with cooking spray. Set aside.
In a large bowl, combine all ingredients for burgers. Using clean hands, mix until well combined. Roll mixture (⅛ cup each) into 28 round mini burgers (like meatballs).
Place burgers onto baking sheet and bake until cooked through about 16-18 minutes.
While burgers are baking, prepare Thousand Island dressing. In a small bowl, mix together the ketchup, mustard, mayonnaise and relish. Next, cut the lettuce into pieces and wash grape tomatoes. Note: These sticks come together quickly, if you prep everything while burgers are baking.
Remove burgers from oven. You’ll notice all the fat from the meat has oozed out onto baking sheet. Using a slotted spoon or spatula, remove burgers to a plate. Dip top of each burger into Thousand Island dressing.
To make each: using a toothpick, add 1 burger, next lettuce and top with 1 grape tomato. Serve immediately. Mini burgers will last in fridge for several days and can be reheated. You can store any leftover burgers in freezer.