Cook noodles in stockpot according to package directions just until tender. Meanwhile, cut each tomato into 8 wedges. Cut each onion into 8 wedges. Set aside. Cut the beef lengthwise in half. Cut across prominent grain into 2 x 1/4 inch slices. Drain the noodles in a colander and return to the stock pot. Add 1 tablespoon sesame oil; toss until well coated. Set aside and cover to keep warm. In a large mixing bowl, combine soy sauce, remaining 1 tablespoon of sesame oil and 1 tablespoon cornstarch, stir until smooth. Add beef and toss to coat. Set aside. In a small mixing bowl, combine broth, sugar, remaining 1 tablespoon cornstarch and vinegar, stir until smooth. Set aside. Heat the wok over high heat about 1 minute or until hot. Drizzle 1 tablespoon vegetable oil into the wok and heat for30 seconds. Add ginger and stir fry about 30 seconds or until fragrant. Add beef mixture and stir fry 5 minutes or until lightly browned. Remove beef mixture to a large bowl and set aside. Reduce heat to medium. Add remaining 1 tablespoon vegetable oil to wok. Add onion wedges; cook and stir about 2 minutes or until tender. Stir in half of the tomatoes. Stir broth mixture mixture until smooth and add to wok. Cook and stir until sauce boils and thickens. Return beef and any accumulated juices to the wok. Add remaining tomatoes; cook and stir until heated through. Transfer noodles to shallow serving bowl, spoon beef mixture over noodles. Sprinkle with green onions.