Preheat oven to 400°F (200°C). Line a baking sheet with foil and place a wire rack on top. Spray the rack with nonstick spray.
Season the wings with salt and pepper, then arrange them in a single layer on the rack. Bake for 40–45 minutes, flipping halfway through, until golden and crispy.
While wings bake, make the glaze: In a saucepan over medium heat, combine pineapple juice, brown sugar, soy sauce, ketchup, vinegar, garlic, ginger, and chili flakes.
Bring to a simmer, stirring occasionally. Mix cornstarch with water, then whisk into the sauce. Simmer until thickened, about 5 minutes.
Once wings are done baking, transfer to a large bowl. Pour the glaze over and toss to coat evenly.
Return glazed wings to the rack and bake for another 10 minutes to caramelize.
Garnish with sliced green onions and sesame seeds. Serve hot and sticky!