1. Soak skewers in water 30 minutes. Preheat grill to medium-high heat (350° to 400°).
2. Combine mirin and next 5 ingredients in a small saucepan over medium-high heat. Bring to a boil, and cook 10 minutes or until slightly thickened and reduced to about 1/2 cup. Let cool. Reserve 3 tablespoons glaze.
3. Thread chicken and green onions evenly onto skewers. Brush skewers with soy glaze.
4. Grill skewers 4 to 5 minutes on each side. Brush with reserved soy glaze before serving.