Cook pasta according to package directions, omitting salt. Drain; set aside.
Whisk together stir-fry sauce and vinegar in large bowl. Add green onions, carrots, bell pepper and cooked pasta; set aside.
Season steak with salt and black pepper. Spray 12-inch skillet with cooking spray. Heat over high heat until hot. Add beef; cook and stir about 4 minutes or until steak is seared and still pink in center. Cook in batches, if needed, to prevent overcrowding.
Add beef to pasta mixture. Toss to coat ingredients evenly with sauce mixture.
Top salad with rice noodes and cilantro, if desired. Serve at room temperature. Refrigerate leftovers.