Toss the tofu with soy sauce, oil, garlic powder, ginger powder, chili powder and black pepper. Add cornstarch and toss until coated, let sit for a minute, toss again.
Preheat the air fryer to 400˚F.
Carefully lift the tofu cubes out of the bowl and place on the hot air fryer basket. Air fry until the tofu is golden brown, shaking the basket every 5 minutes, about 20 minutes total. Garnish with green onions and serve immediately.
Notes
Tip: To get the crispiest tofu, don't overcrowd the air fryer basket. If you have too many pieces of tofu in the basket, they will likely steam over getting crispy.