01 - Whisk together soy sauce, pineapple juice, brown sugar, ketchup, rice vinegar, ginger, garlic, sesame oil, honey, smoked paprika, and pepper in a large bowl until completely smooth and sugar has dissolved.
02 - Measure out 1/2 cup of the prepared marinade and transfer to a separate container. Cover and refrigerate for later use during grilling.
03 - Place chicken pieces in a large resealable plastic bag or shallow glass dish. Pour the remaining marinade over the chicken, turning pieces to coat evenly. Seal or cover and refrigerate for minimum 2 hours, preferably overnight for maximum flavor penetration.
04 - Prepare grill to medium-high heat, approximately 400°F. Lightly oil the grates to prevent sticking and ensure clean release.
05 - Remove chicken from marinade, allowing excess to drip off. Discard the used marinade. Pat the surface lightly with paper towels for better caramelization.
06 - Place chicken on the grill skin side down. Sear for 6-8 minutes until golden brown marks appear, then flip and cook opposite side for another 6-8 minutes.
07 - Brush the reserved marinade generously over the chicken. Continue grilling, turning and basting every 2-3 minutes, until meat reaches internal temperature of 165°F and develops a rich, caramelized glaze, approximately 10-15 additional minutes.
08 - Transfer chicken to a platter and allow to rest for 5 minutes, letting juices redistribute. Sprinkle with scallions, sesame seeds, and fresh pineapple. Serve immediately while hot.