In a large bowl, mix together ground beef, salt, pepper, and corn starch. Gather meat in hand and throw against the side of the bowl for about 3 to 4 minutes. Meat will come together in a ball.
Shape into 1¼-inch diameter meatballs.
Place meatballs onto a non-stick baking pan and bake in 350°F (180°C) oven for 30 minutes. Remove and set aside.
Mix all sauce ingredients together in a small bowl.
Heat 1 tablespoon vegetable oil in a large wok or pan over medium high heat. Sauté onions until lightly brown.
Add red bell peppers and snow peas. Stir-fry for 2 to 3 minutes until vegetables turn to a bright color. Remove and set aside.
Heat remaining tablespoon of vegetable oil and sauté garlic for 30 seconds.
Pour in sauce mixture. When sauce comes to a boil and thickens, add cooked meatballs. Allow meatballs to cook through.
Finally, add cooked vegetables and pineapples. Stir to get everything well coated with sauce, about 1 to 2 minutes.