Heat 3 inches of oil in a large pan to 360°.
Place the chicken breast pieces in a large bowl. Combine the eggs, cornstarch, flour and salt and pour over the chicken and toss to coat well.
Fry some of the chicken in the oil, making sure not to overcrowd the pan. When the chicken is golden brown, remove and place on a paper towel lined plate.
Continue until all the chicken has been fried.
In another pan, simmer the orange juice, brown sugar, vinegar, soy sauce, garlic, ginger and sesame oil for 3 minutes. Stir the cornstarch into the water and whisk into the sauce. Continue to cook until the sauce begins to thicken.
Add the chicken to the sauce and toss to coat.
Serve with a sprinkle of zest, green onions and sesame seeds.