1.Heat a medium frying pan over medium heat. Add rice; toast, stirring frequently, for 5 minutes or until fragrant and light golden. Transfer to a mortar and pestle; pound until finely ground.
2.Place tamari, sake, mirin, sugar and spice in a small saucepan over medium heat. Bring to a simmer; cook 2 minutes or until sugar dissolves. Remove from heat, add rind and oil. Transfer to a small bowl; refrigerate marinade until cool.
3.Combine tenderloins with marinade; refrigerate 3 hours or overnight.
4.Preheat a barbecue or grill pan over high heat. Drain chicken tenderloins from marinade; reserve marinade in a small bowl. Thread one tenderloin onto each skewer in a `S’ shape. Cook skewers,brushing with reserved marinade, for 8 minutes, turning frequently, until charred and chicken is cooked through.
5.To serve, place skewers on a platter, sprinkle over toasted rice and green onions.
Soak bamboo skewers for at least 30 minutes before using, to prevent burning when cooking. Do-ahead: Chicken can be skewered and marinated a day ahead. You will need 24 x 15cm (6-inch) bamboo skewers.Note