Cut the chicken into bite sized pieces and refrigerate until 15-20 minutes before you are ready to fry. Dry the chicken pieces off again with paper towels and discard. Lightly salt and pepper the chicken pieces.
Heat the oven to 200 degrees F. Pour the cornstarch into a medium sized bowl. Add the chicken and stir until it is completely coated. Add 1/2 -3/4 " of oil to the skillet and heat on high. Use an instant thermometer to check the temperature often and bring to 360 degrees F.
Add a few chicken pieces to the batter at a time, using tongs to shake off the excess batter before setting gently into the hot 360 degree oil. Repeat until the skillet is full of chicken pieces but they are not crowded. Turn when they are light golden brown. Remove pieces to a wire rack over a cookie sheet lined with parchment or paper towels. Move to the oven to keep warm.
Fry the remaining chicken pieces in batches. Move to the oven to keep warm. Keep the skillet burner on high or close to high for the double fry. Check the oil and bring to 380 degrees F.
Add the chicken pieces back into the skillet for 1-2 minutes, stirring with a slotted spoon or tongs until crisp and very golden brown. Remove to the wire rack again.
Turn the burner under the oil off.
Spoon the chicken pieces onto a serving plate and spoon the warm sauce over the top. Add sliced green onions and sesame seeds. Add a few orange slices for decoration. Serve with hot steamed white rice.