Orange Chicken Sauce:

1. In a medium saucepan, combine the sugar, vinegar, soy sauce, water, and zest and juice of an orange. Whisk together and bring to a boil over high heat. Reduce the heat to medium and whisk in the Shaoxing wine and Chinkiang vinegar, if using. Simmer for 8-10 minutes or until the sauce reduces by about 25%. 
2. In a small bowl whisk together the cornstarch and water until the cornstarch dissolves. Whisk the slurry into the sauce and simmer until it thickens. Remove from heat and immediately stir in the garlic, ginger and chilies. Let steep in the warm sauce while you cook the chicken. 

‍Fried Chicken:

1. Season the chicken pieces generously with salt. 
2. In a medium bowl, whisk together the cornstarch and flour until evenly combined.
3. In a separate bowl, whisk together the eggs with a splash of water.
4. Fill a 5 quart (4.7L) heavy bottomed pot just over halfway with oil. Heat to 375℉ (190℃). Line a baking sheet with a cooling rack and place that next to the hot oil.
5. Add the chicken to the cornstarch mixture, in batches, and firmly press the dredge into the chicken, making sure each piece is thoroughly coated. Shake off any excess cornstarch and place the chicken in the egg mixture, tossing to coat completely. Add the chicken pieces back into the cornstarch mixture and toss to completely coat. Place on a baking sheet and repeat with the rest of the pieces of chicken. 
6. Carefully add the chicken, in batches, to the hot oil and fry for 3-5 minutes or until the chicken is a light golden brown and crispy on the outside and cooked to 165℉ (74℃) internally. Drain on the cooling rack. Repeat with the remaining batches of chicken.  
7. Add the fried chicken to a large bowl and pour in the sauce. Toss the chicken in the sauce until fully coated. Add to a plate and top with green onions and sliced chilies. Serve.