In a gallon-sized zippered plastic bag, place the chicken pieces. In a small bowl, whisk together the soy sauce, pineapple juice, ketchup, brown sugar, olive oil, sesame oil, garlic, ginger, salt, and pepper. Reserve ⅔ cup of this marinade in a small container and refrigerate for later. Pour the remaining marinade over the chicken, seal the bag, and refrigerate for at least 1 hour, up to 3 hours. If using wooden skewers, soak them in water during this time to prevent burning.

Preheat your grill to medium heat. In a large bowl, toss the pineapple, bell peppers, and onion with 2 tablespoons of olive oil, ¼ teaspoon salt, and ¼ teaspoon pepper. Thread the chicken, veggies, and pineapple onto the skewers, alternating as you go. Discard the marinade used for the chicken.

In a small bowl, mix the cornstarch and water. In a small saucepan over medium-low heat, pour in the reserved marinade and add the cornstarch mixture. Stir and cook until the sauce thickens, then remove from heat and set aside.

Brush the grill grates with olive oil if needed. Place the skewers on the grill and cook for 5 to 6 minutes until browned. Flip the kabobs, brush the grilled side with the basting sauce, and cook for an additional 4 to 5 minutes, or until the chicken reaches an internal temperature of 165°F (75°C). Flip once more and brush with any remaining basting sauce.

Transfer the kabobs to a serving platter and enjoy!