Preheat the oven to 140°C. In a large bowl, combine baking powder, salt, pepper, garlic powder, chilli, and smoked paprika.
Use a paper towel to lightly pat dry the chicken wings. Add them to the spice mixture and toss to coat thoroughly.
Place a wire rack inside a large baking dish. Place the wings on the rack in a single layer (this will allow for airflow underneath to ensure crispy and evenly cooked wings). Place the baking dish into the oven for 30 minutes. Turn the oven up to 220°C and cook for another 30 minutes.
When the wings have 15 minutes remaining, combine all the ingredients for the sweet and spicy glaze in a saucepan and bring to a simmer until the wings are cooked.
Remove the wings from the oven and drizzle the sweet and spicy glaze over them. Toss to coat.
Allow the wings to cool slightly before garnishing with thinly sliced spring onions, sesame seeds, and sliced chilli.