Trim off excess fat from the chicken thighs and discard. Cube the chicken into small, 1/2 inch cubes.
Place the cubed chicken into a large bowl with the salt, pepper, tapioca, and 1 tablespoon of the coconut aminos. Toss until well combined.
Heat oil large wok (or skillet) over medium-high heat. When the oil is hot and just begins to smoke, add the chicken in a single layer (you may need to do this in two batches) and cook until the chicken is golden brown and just cooked through. (If you are doing this in two batches, transfer the cooked chicken to a plate and set aside).
Add all the chicken back into the wok along with the green onions, mushrooms, garlic, ginger, toasted sesame oil and remaining tbsp of coconut aminos. Add the red pepper flakes (if using). Cook, stirring, until the green onions are tender, 2 to 3 more minutes.
Remove from heat and serve in cabbage leaves. Enjoy!