In a large saucepan over medium heat, combine all the sauce ingredients. Bring to a boil, then reduce the heat to a simmer. Allow the sauce to reduce by a quarter, about 10-15 minutes.
While the sauce is reducing, make the batter. Whisk together the coconut aminos and whisked egg. Slowly add the arrowroot powder until you have the consistency of a thick pancake batter. Gently stir in the sparkling water.
Place the cooking fat in a heavy stockpot over medium-high heat, using a candy thermometer to monitor the temperature. When it reaches 375°F, dip the chunks of chicken into the batter and then place them in the hot fat in batches, so as not to overcrowd the pot. Fry until fully cooked and crispy, about 4-6 minutes. Remove and allow to drain on a paper towel.
Toss the fried chicken with the sauce. Garnish with the orange zest and sliced green onion and serve.