In a pot, combine the cider vinegar, brown sugar and chili-garlic sauce and whisk together. Bring the sauce to a simmer and reduce the heat to medium-low. Simmer the sauce, uncovered, until it is reduced to a syrup (about 1 1/2 cups finished volume). Season with 1 tablespoon salt and 1 teaspoon pepper, or to taste. Cool the sauce before using.
In a large pot, heat the oil to 250 degrees F. Pat the chicken wings dry with paper towels and then gently lower them into the oil. Cook the wings until they float, 10 to 12 minutes. Remove the wings from the oil, drain and cool. (Do not discard the oil.) Refrigerate the wings until serving.
To serve, reheat the oil to 350 degrees F. Fry the pre-blanched wings until crispy and browned, 3 to 5 minutes. Remove the wings from the oil and allow them to drain. Transfer the wings to a large bowl and season with salt and pepper. Pour the sauce over the wings and toss to coat.