Mix the ground beef, cracker crumbs, onion, egg, salt, ginger, and milk together and shape into rounded tablespoon sized balls.
In a large saucepan on medium heat, cook the meatballs for 10 minutes turning often to brown all sides. Place the meatballs in a bowl to the side and drain any fat from the meatballs. Set the pan aside to use for the sauce.
In a small bowl mix the cornstarch and the sugar until combined. Add in the reserved pineapple juice, vinegar and soy sauce and whisk until well combined.
Return the pan to medium heat and add the sauce. Bring to a boil and stir for about 1 minute until it thickens up.
Add in the pineapple and the green peppers and stir to combine. Gently add in the meatballs and return the mixture to a simmer for 1 minute. Remove from heat and serve.
Notes
This dish is great served with rice or vegetables.