For the sauce, mix all the ingredients in a pot and set aside.
Cut the chicken into small pieces and place in a bowl. Mix in egg and season with salt and pepper. Add 1 tablespoon of oil and mix well.
Combine cornstarch and flour in a large bowl. Add chicken pieces and toss to coat well.
Heat oil in a skillet. Successively add chicken pieces and fry for 3-4 minutes until golden brown. Remove chicken pieces from oil with a slotted spoon and drain on paper towels. Set aside.
Clean skillet and heat vigorously for 15 seconds. Pour 1 tablespoon oil into the hot pan, add peeled and grated ginger and finely chopped garlic and stir-fry. Finely chop the onion and stir-fry. Pour in rice wine and stir in briefly, then add orange sauce and bring to a boil.
Fold in the chicken and mix well with the sauce.
Mix water with remaining tablespoon of cornstarch until smooth. Add to the chicken and heat until the sauce has thickened. Stir in one tablespoon of sesame oil and season with chili powder.
Serve orange chicken on a bed of rice.