Combine sugar, spices, salt, orange juice, vinegars, and soy sauce in medium bowl. Slowly mix in the olive oil, whisking constantly to create an emulsion. Add scallions, shallots, garlic, ginger, and Jalapeño. (To increase the heat from the marinade use a Habanero chile instead of the Jalapeño chile.) Set aside for one hour.
Rinse chicken and pat dry. Rub jerk sauce under and over chicken skin. Cover and refrigerate at least 4 hours or overnight.
Prepare medium-hot indirect grill. Sear chicken over direct heat, about 5 minutes per side. Move to indirect heat and cook at 250F for one hour, turning and basting with jerk sauce every 15 minutes.