Cook rice according to package directions. Meanwhile, in a small bowl, combine the cornstarch, sugar, ginger and orange zest. Stir in orange juice and soy sauce until smooth; set aside.
In a large skillet or wok, stir-fry the celery, carrots and cashews in oil until vegetables are crisp-tender. Stir cornstarch mixture and add to the pan. Bring to a boil; cook and stir for 1 minute or until thickened. Add pork; heat through. Serve with rice; top with noodles and onion.