1. Soak 12 bamboo skewers in water for at least 15 minutes.
2. In a small saucepan over medium heat, stir together mirin, soy sauce, and sugar until sugar dissolves, about 2 minutes (it may come to a low simmer). Remove from heat; set aside.
3. Preheat grill to high heat. Assemble skewers: thread each skewer with a piece of pepper first, then a piece of chicken, then a piece of scallion (spear scallion piece horizontally, not through hollow part). Repeat so that each skewer has roughly three sets of each ingredient.
4. Grill skewers for 5 minutes on each side. Using a pastry brush, coat top surface of skewers with basting sauce. Let skewers grill 3 minutes. Flip and coat second side of each skewer with sauce; let grill another 3 minutes.
5. Continue to grill, flip, and brush skewers with sauce for about 5 more minutes, until basting sauce is gone, chicken is cooked through (check doneness by cutting into a piece), and a little bit of char shows up on tips of chicken and vegetables. Transfer cooked skewers to a clean plate; serve hot.
Source: Hannaford fresh Magazine, May - June 2008