In a small bowl whisk the soy sauce, vinegar, water, sugar, garlic, ginger and red pepper flakes until sugar is dissolved.
Place chicken wings in a large ziplock freezer bag, pour in 1/3 of the marinade mixture. Seal and mix the wings around in the marinade. Place in refrigerator for 4 hours or preferably overnight for best flavor.
Place the rest of the marinade in a small saucepan and whisk in cornstarch until blended. Bring sauce to a boil and reduce heat and simmer 20 minutes or until thickened.
Preheat oven to 425 degrees
Place a metal wire cooling rack on a rimmed foil lined baking sheet. Place all the wings on the wire rack
Bake for 30-35 minutes
Turn the oven to broil, brush some of the teriyaki sauce over the wings and broil 3-5 minutes. Flip the wings and repeat.
Garnish with green onion and sesame seeds. Serves 4-6
**note I usually buy the 3 lb bag of chicken, the wings tend to be a little larger