Cut each wing at the joint, so you have a wing and a drum. Clean the wings in a water bath made with lemon juice and vinegar. Pat the wings dry with paper towels to remove as much moisture as you can.
Season the wings with salt. In a small bowl, combine onion powder, garlic powder, ginger powder, smoked paprika, black pepper, and marjoram, together. Whisk well to combine. Pour oil over the wings. Then sprinkle the seasoning mixture over the wings. Toss wings through the seasoning until coated.
Cover the wings and place them in the fridge and leave them to marinate for at least 1 hour. Remove the wings from the fridge and sprinkle the baking powder over them and toss them together to make sure the baking powder coats all of them.
Adjust the oven rack to the middle position and preheat the oven to 200°C or 390°F
Line a rimmed baking tray with an oven liner or aluminium foil and set a wire rack inside.
Arrange the wings on the rack in a single layer.
Bake for 20 minutes, flip, and continue to cook for another 20 minutes, until golden brown and crispy. The cooking time may vary depending on the size of the wings. The internal temperature of the wings should read 73° C or 165 °F.