In a small bowl, whisk together 3 tbsp arrowroot starch and garlic powder. Place inside an air tight container or ziploc bag. Place the starch in the container with the chicken, and shake until each piece is coated. Place the chicken inside the air fryer basket, and spray with oil on both sides of the chicken.
Set the air fryer timer to 12 minutes and 370 degrees (please note that different air fryers cook differently and it may need to cook longer or shorter). Check at the halfway mark and toss so it cooks evenly on both sides.
While chicken is cooking, make the sauce. In a small sauce pan, whisk together coconut aminos, vinegar, orange juice, zest, ginger and garlic. Whisk in the remaining 1/2 tbsp of arrowroot, and cook over medium heat until thick (2-3 minutes). Remove from heat.
If using the stovetop, heat a large skillet to medium/medium high heat. Once hot, toss in 3 tbsp olive oil or avocado oil. Add chicken and cook on both sides consistently flipping so the starch doesn't stick to the pan. Cook until golden brown and chicken is completely cooked through (about 10-12 minutes).
Once chicken is cooked, toss in a large bowl with sauce. Sprinkle with sesame seeds and green onion to serve.