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 combined and sugar dissolves.
02 - Measure out 1/2 cup of the prepared marinade and transfer to a separate container. Cover and refrigerate for use as a basting glaze during cooking.
03 - Place chicken thighs and drumsticks in a large resealable plastic bag or shallow glass dish. Pour the remaining marinade over the pieces, turning to coat evenly. Seal or cover and refrigerate for at least 2 hours, preferably overnight for maximum flavor penetration.
04 - Prepare grill for medium-high heat cooking, targeting 400°F. Lightly oil the grates with a high-heat oil to prevent sticking.
05 - Remove chicken from the marinade and discard the used liquid. Pat the pieces dry with paper towels to promote proper searing and caramelization.
06 - Arrange chicken skin-side down on the preheated grill. Cook undisturbed for 6-8 minutes until well-marked and crispy. Flip each piece and cook an additional 6-8 minutes on the second side.
07 - Begin brushing chicken with the reserved marinade. Continue grilling, turning and basting every 2-3 minutes, until the meat reaches an internal temperature of 165°F and develops a rich caramelized coating, approximately 20-25 minutes total grilling time.
08 - Transfer chicken to a cutting board or platter. Allow to rest for 5 minutes to let juices redistribute. Garnish with sliced scallions, toasted sesame seeds, and diced fresh pineapple. Serve immediately while hot.