In a bowl, combine the chicken, egg white, tamari/soy sauce, orange zest, and pepper. Toss well to coat. In a separate bowl, add the cornstarch.Dredge the chicken through the cornstarch to coat. In a glass jar, whisk together the broth, orange juice, tamari/soy sauce, rice vinegar, and honey. Heat the avocado oil in a large skillet over medium heat. Add the chicken, working in batches, cook until golden all around, about 5 minutes. Remove the chicken from the skillet. To the skillet, add the garlic, ginger, and chili flakes. Cook 1-2 minutes. Pour in the orange sauce. Bring to a boil, boil 3-4 minutes, then add the chicken. Toss with the sauce and cook until the sauce thickens around the chicken, about 5 minutes. Serve the chicken and sauce over steamed rice with sesame seeds and green onions.