Preheat your grill to medium-high heat (about 375°F to 400°F).
In a large bowl, combine the chicken, pineapple, red bell pepper, green bell pepper, red onion, BBQ sauce, soy sauce, olive oil, garlic powder, ground ginger, black pepper, and salt. Mix well until all ingredients are evenly coated.
Lay out the aluminum foil sheets on a flat surface. Divide the chicken and vegetable mixture evenly among the sheets, placing it in the center of each.
Fold the sides of the foil over the mixture, then fold the ends to create a sealed packet, ensuring there are no openings for steam to escape.
Place the foil packets on the preheated grill and cook for 20-25 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F.
Carefully remove the packets from the grill and let them sit for 5 minutes before opening. Be cautious of steam when opening the packets.
Serve the contents of the packets in bowls, garnished with chopped green onions and sesame seeds if desired.