01 - In a large bowl, whisk together soy sauce, pineapple juice, brown sugar, ketchup, rice vinegar, ginger, garlic, sesame oil, honey, smoked paprika, and pepper until thoroughly combined.
02 - Measure out 1/2 cup of the prepared marinade and set aside separately for basting during grilling.
03 - Place chicken pieces in a large resealable bag or shallow dish. Pour remaining marinade over the chicken, ensuring all pieces are evenly coated. Cover and refrigerate for at least 2 hours, or overnight for maximum flavor.
04 - Preheat grill to medium-high heat (approximately 400°F). Lightly oil the grates to prevent sticking.
05 - Remove chicken from marinade and discard the used liquid. Pat chicken pieces dry with paper towels.
06 - Place chicken on the grill skin side down. Grill for 6-8 minutes, then flip and grill for an additional 6-8 minutes.
07 - Brush chicken with the reserved marinade. Continue grilling, turning and basting every 2-3 minutes until cooked through and caramelized, approximately 20-25 minutes total. Internal temperature should reach 165°F.
08 - Remove chicken from grill and let rest for 5 minutes. Garnish with sliced scallions, toasted sesame seeds, and diced pineapple if desired. Serve hot.