Preheat oven to 425 degrees F. Line a large rimmed baking sheet with heavy duty aluminum foil and coat the foil generously with non-stick cooking spray.
In a small bowl mix together the garlic pepper, salt, and cayenne pepper. Place chicken wings in a large bowl and sprinkle seasoning mix over the top. Mix the wings well by hand till well coated with seasoning. Pour the wings out on to the foil lined baking sheet and spread them out evenly. Place them in the oven and bake for 35 minutes or till golden brown. Remove from oven and reduce oven temperature to 375 degrees F.
While the wings are baking, combine hoisin sauce, soy sauce, ketchup, brown sugar, dry sherry, ginger root, and garlic in a medium bowl. Refrigerate until wings come out of the oven.
Line a second rimmed baking sheet with heavy duty aluminum foil and spray it generously with non-stick cooking spray. Transfer the partially cooked wings to the prepared baking sheet. Drizzle about half of the sauce over the top of the wings. Mix well with a spoon or tongs until all of the wings are coated with sauce. Sprinkle wings with sesame seeds and toss lightly. Place back in the oven and bake for an additional 10 to 15 minutes or until they appear to be crisped and cooked through. Watch closely and make sure to pull them out of the oven before the sauce begins to burn.
While wings are cooking, transfer remaining sauce to a small saucepan and place over low heat. Simmer on low until wings are ready.
Transfer wings to serving platter and sprinkle with green onion. Serve with additional warmed sauce on the side.