01 -
In a medium bowl, whisk together ketchup, dark brown sugar, soy sauce, pineapple juice, 2 tablespoons olive oil, rice vinegar, garlic, ginger, and sesame oil. Season with 3/4 teaspoon freshly ground black pepper and salt if desired.
02 -
Place chicken pieces in a gallon-sized resealable bag. Reserve 1/2 cup of the marinade in the refrigerator. Pour the remaining marinade over the chicken, seal the bag, and turn to coat. Refrigerate for 1 hour to allow the flavors to develop. While marinating, soak 10 wooden skewers in cold water for 1 hour.
03 -
Drizzle the remaining 2 tablespoons olive oil over the red onion, green bell pepper, and pineapple. Toss to coat evenly. Season the onion and bell pepper with salt and freshly ground black pepper.
04 -
Thread red onion, bell pepper, pineapple, and marinated chicken onto the prepared skewers, alternating ingredients until all the chicken is used.
05 -
Preheat grill to medium heat, about 400°F (200°C). Brush grill grates with olive oil. Place skewers on the grill and cook for 5 minutes. Brush the tops with 1/4 cup of the reserved marinade, then rotate skewers and brush the other side with the remaining 1/4 cup marinade.
06 -
Continue grilling for about 4 minutes longer, or until the chicken reaches an internal temperature of 165°F (75°C) at the center. Remove from grill and serve warm.