Cut the chicken into bite-sized, 1-inch pieces and place them in a bowl. Pour in the orange juice, mix to coat, then cover and let it marinate for at least an hour or up to overnight.
In a large cast iron skillet, heat about an inch of oil to 350ºF (180ºC). (This is usually when I get to work on my sauce; instructions below, and let it gently simmer on the lowest setting while I continue with the chicken)
Set up your dredging station: In one shallow bowl, beat the eggs. In another, combine the flour, cornstarch, salt, and pepper. Working in batches, dip the marinated chicken into the egg, then coat it in the flour mixture, shaking off any excess.
Fry the chicken in batches until it's crispy and golden on both sides, about 4 minutes per side. Transfer to a paper towel-lined plate to drain and repeat with the rest of the chicken.
Place the crispy chicken in a mixing bowl, pour the sauce over the top, and toss until evenly coated.
Garnish with the remaining green onions and serve with a side of rice.