Preheat oven to 425 degrees F. Spray a large rimmed baking sheet with cooking spray and set aside.
Using 2 pie plates, add the beaten eggs to one and toss the panko and flour in the other. Dredge each chicken piece in the egg and then in the panko mixture and add to the prepared baking tray. Repeat with remaining chicken. Bake for 10 minutes and turn the pieces, then continue to cook for another 10 minutes, or until chicken is done to your liking.
Meanwhile, add the orange juice, soy sauce, brown sugar, mirin, sriracha, garlic and ginger to a medium saucepan. Bring to a low boil, stir occasionally, turn heat down to low. When the chicken is just about done, add the cornstarch to the orange juice mixture and bring to a boil. Heat until thickened enough to coat a spoon. Remove from the heat.
In a large serving bowl add the cooked chicken and top with the orange sauce, toss lightly to coat. Sprinkle with sesame seeds and green onions and serve with steamed white rice.