1. Preheat oven to 300°F. Line a rimmed baking sheet with several layers of foil. Combine garlic, ginger, soy sauce, ketchup, rice vinegar, sesame oil, sugar and red pepper in a food processor and process until smooth. Reserve 1/2 of sauce in 2 small bowls. Transfer remaining sauce to a large bowl. Add chicken wings; toss to coat. Arrange wings skin side down in a single layer on prepared baking sheet.
2. Bake wings 45 minutes, flipping halfway through. Increase oven temperature to 450°F. Brush wings with 1 portion of reserved sauce and bake, turning wings occasionally, until wings are lacquered with some slightly charred spots, about 15 minutes. Brush with remaining reserved sauce, sprinkle with sesame seeds and scallions; serve.