Heat cooking oil in pan over medium high heat.
Saute garlic and onion until onion is soft.
Add peppers and saute for a minute.
Add soy sauce, sugar, water, vinegar, and crushed pineapples.
Season to taste.
Stir in corn starch slurry to thicken sauce.
Add prepared meatballs, and toss to coat.
Remove from heat, garnish, and serve.