Rinse the wings under cold running water, then drain and blot dry with paper towels. Make 2 or 3 deep slashes, to the bone, in the meaty part of each wing. Place the chicken in large nonreactive bowl and then stir in next 6 ingredients. Cover and let marinate, in the refrigerator, for 4 hours, turning the wings occasionally.
Meanwhile, prepare the barbecue sauce. Heat oil in a medium-size heavy saucepan over medium heat. Add onion, garlic, ginger and hot pepper flakes and saute, stirring with a wooden spoon, until the onion and garlic are lightly browned, about 5 minutes. Stir in remaining ingredients and bring to a boil. Reduce heat to low and simmer the sauce gently until thick and richly flavored, 10 to 15 minutes, stirring occasionally. Remove from heat and measure out about 1 cup. Set it aside for serving.
Preheat the gril to medium-high.
When ready tto cook, oil the grill grate. Drain the wings and arrange them on the hot grate, pulling them open to expose as much skin as possible to the flames. Grill, turning several times with tongs, until the thicker wing sections are no longer pink near the bone, 12 to 16 minutes in all. Start brushing the wings with sauce the last 5 minutes, then transfer to a platter and brush with sauce again.
Serve accompanied by the reserved sauce.