01 - Whisk together soy sauce, pineapple juice, brown sugar, ketchup, rice vinegar, ginger, garlic, sesame oil, honey, smoked paprika, and black pepper in a large bowl until fully incorporated.
02 - Measure out 1/2 cup of the marinade and set aside in a separate container for basting during cooking.
03 - Place chicken pieces in a large resealable bag or shallow dish. Pour remaining marinade over chicken, ensuring complete coverage. Refrigerate for 2 hours minimum or overnight for maximum flavor penetration.
04 - Heat grill to medium-high temperature (400°F). Clean grates and lightly oil to prevent sticking.
05 - Remove chicken from marinade and discard used liquid. Pat surface dry with paper towels for better searing.
06 - Place chicken skin side down on grill. Cook for 6-8 minutes until skin begins to crisp and char marks form.
07 - Turn pieces over and grill for another 6-8 minutes on the second side.
08 - Brush chicken with reserved marinade. Continue grilling, turning and basting every 2-3 minutes until internal temperature reaches 165°F and exterior develops caramelized coating, approximately 20-25 minutes total cooking time.
09 - Transfer chicken to platter and let rest 5 minutes to redistribute juices. Garnish with scallions, sesame seeds, and diced pineapple. Serve immediately.