Begin by preparing the skewer sticks, add the pepper, onion and pineapple to each stick then carefully place the chicken on the sticks, then additional pepper, onion, and pineapple.
Warm up the olive oil in a medium sized sauce pan on medium-high heat, add in the garlic clove, 1 1/2 Cups water, sugar, vinegar, soy sauce, and the reserved pineapple juice.
Let this warm up to a boil, then whisk in the ketchup, 1/4 cup water, and cornstarch.
Pour 1/4 cup of the sauce into a small bowl and reserve the rest.
Brush the sauce over the chicken and let sit for about 20 minutes.
While it is sitting, warm the grill up to medium-high heat.
Place the skewers on the grill and cook on both sides for about 10-15 minutes, when rotating them add additional sauce. They should be 165* internally before eating.