For the wings: In a large bowl, combine the cayenne, white pepper and 1/2 teaspoon salt. Add the chicken wings, bell peppers and serrano chiles. Drizzle with the vegetable oil and then, using clean hands and preferably wearing gloves, massage the seasoning mixture into the wings, peppers and chiles. Set aside.
For the sauce: To a medium saucepan over medium heat, add the soy sauce, vinegar, honey, brown sugar, granulated sugar, sesame oil, garlic, pineapple and ginger and stir to combine. Cook over medium heat until reduced by half and thick enough to coat the back of a spoon, about 15 minutes. Cool slightly.
Pour half of the cooled sauce over the wings and peppers, reserving the other half for the finished wings.
Heat a grill pan or a gas or charcoal grill over medium-high heat. Place the wings, peppers and chiles on the grates in a single layer and cook until nicely charred, 6 to 8 minutes per side. Transfer to a serving platter. Pour the remaining sauce over the cooked wings. Garnish with the sesame seeds and green onions.