Begin by cutting the chicken into small cubes, set aside.
Warm up the olive oil in a cast iron skillet along with the garlic.
Add the chicken and cook until well done.
While the chicken is cooking in a medium sized saucepan, add the pineapple chunks with juice, pepper, onion, 1 1/2 Cups water, sugar, and vinegar. Whisk well then add the soy sauce and ketchup.
Whisk well until it reaches a boil.
Once boiling, whisk in the cornstarch and water and stir until it's thickened.
Serve the cooked rice, topped with the cooked chicken and add the sauce.