Combine soy sauce, water, rice vinegar, fresh ginger, garlic and sesame oil in a small saucepan.
Heat until it begins to simmer.
Meanwhile, combine cornstarch and water to make a slurry to thicken the sauce. Add it to the simmering sauce and continue cooking until sauce has thickened slightly and is glossy, about 45 seconds to 1 minute. Remove from heat.
Toss chicken wings with baking powder.
Arrange in a single layer in air fryer basket. You may need to cook these in batches, depending on the size of your air fryer.
Fry at 400°F. for 10 minutes, then shake or flip. Cook for 10 minutes more. Check internal temperature. If it's below 165°F. continue to cook for 5 minutes more.
Remove from air fryer, transfer to a bowl and toss with teriyaki sauce. Sprinkle with sesame seeds and or sliced green onions, if desired. Serve.
See instructions in post for how to cook these teriyaki wings in the oven.