In a large nonstick skillet, heat oil over high heat. Add pork and onion; stir-fry 4 to 5 minutes or until pork is lightly browned and onion is tender; set aside.
For dressing, whisk together orange juice, vinegar, salt, pepper and orange zest.
In a large serving bowl toss together pork and onion, pasta, broccoli, cherries and walnuts with dressing. Serve with crusty hard rolls.