Cover tightly and simmer 45 minutes, turning riblets occasionally. Meanwhile, combine remaining orange juice, soy sauce, honey, garlic, ginger and orange peel in small saucepan. Dissolve cornstarch in 1 tablespoon cold water. Bring to a boil over medium-high heat, stirring constantly. Cook and stir 1 minute.
Place riblets on grid over medium coals.
Brush with glaze. Grill 12 to 14 minutes or until evenly browned, turning frequently and brushing with glaze. Or, broil 4 inches from heat, turning frequently and brushing with glaze, about 12 minutes. Transfer to platter and sprinkle with green onion. Cut into serving-size portions.