Make the Marinade:
In a medium bowl, whisk together pineapple juice, soy sauce, brown sugar, ketchup, vinegar, ginger, garlic, and optional sesame oil and paprika.
Marinate the Chicken:
Place chicken in a large zip-top bag or bowl.
Pour in about two-thirds of the marinade (reserve the rest for basting).
Refrigerate for at least 4 hours, preferably overnight.
Grill the Chicken:
Preheat grill to medium heat. Oil the grates to prevent sticking.
Grill chicken for 6–7 minutes per side, basting with the reserved marinade as it cooks.
Turn frequently (“huli huli!”) to prevent burning and build flavor.
Cook until internal temp reaches 165°F (75°C).
Serve:
Let chicken rest for a few minutes before slicing.
Serve with rice, grilled pineapple, or a fresh salad.