In a large bowl, combine flour, salt, and pepper. Dredge the chicken pieces in the flour mixture, shaking off any excess. Dip the floured chicken into the beaten eggs, then coat with panko breadcrumbs. Set aside.

In a medium saucepan over medium heat, combine orange juice, sugar, soy sauce, rice vinegar, cornstarch, ginger, garlic, and sesame oil. Stir until the mixture thickens and becomes syrupy, about 5-7 minutes. Remove from heat and set aside.

In a large skillet or deep fryer, heat oil over medium-high heat. Fry the breaded chicken pieces in batches until golden brown and cooked through, about 5-7 minutes per batch. Use a slotted spoon to transfer the chicken to a paper towel-lined plate to drain excess oil.

In a large bowl, toss the crispy chicken with the orange sauce until well coated.

Serve the orange chicken hot, garnished with sliced green onions and sesame seeds.