In a small bowl, whisk together the orange juice, orange zest, coconut aminos, rice vinegar, red pepper flakes, and a pinch of salt and pepper; set this sauce mixture aside.
Heat 1/2 tablespoon avocado oil in a medium high-sided frying pan over medium heat. Add the minced ginger and garlic and cook, stirring, until fragrant, about 1 minute.
Add the orange juice mixture to the pan and stir to combine with the garlic and ginger.
Bring the sauce to a boil over high heat. Place 1 teaspoon tapioca starch in a medium bowl, add 2 teaspoons of the hot sauce to the starch, and whisk until smooth; then whisk that mixture back into the boiling sauce.
Boil the sauce for 2 minutes, then reduce heat to medium-low and cook another 3–4 minutes until thick and glossy. Transfer the sauce to a large bowl and cover while you cook the chicken.
Heat about 1 tablespoon of the frying oil in a large skillet over medium-high heat (use two batches and 1 tablespoon oil each time to avoid crowding the pan).
Place 3 tablespoons tapioca starch and a pinch of salt and pepper into a zip-top bag. Add the chicken cubes, seal the bag, and shake to coat the chicken evenly.
Fry the coated chicken in the hot oil without crowding, cooking about 2–3 minutes per side until golden brown and crispy; adjust heat if they brown too quickly. Repeat with remaining chicken and oil as needed.
Transfer cooked chicken to a paper towel-lined plate to drain excess oil. Add the chicken to the bowl with the sauce, add the orange segments, and toss gently until coated.
Serve the orange chicken over hot white rice or cauliflower rice and garnish with sliced green onion and sesame seeds.
