Combine 1 tablespoon each teriyaki sauce and chili oil in a large bowl. Cut beef across prominent grain into 1/8 inch thick slice; cut each slice into 1 1/2 inch pieces. Toss beef with teriyaki mixture.Combine remaining 4 tablespoons teriyaki sauce, sherry, and cornstarch in a small bowl; stir until smooth.Heat the wok over high heat about 1 minute or until hot. Drizzle 1 tablespoon peanut oil into the wok and heat for 30 seconds. Add half of the beef mixture; stir fry 2 minutes or until beef is barely pink in the center. Remove beef to a large bowl. Repeat with the remaining beef mixture.Reduce heat to medium high.Heat remaining 1 tablespoon peanut oil in the wok. Add mushrooms and onion; stir fry 5 minutes or until vegetables are tender.Stir teriyaki mixture until smooth and add to the wok. Stir fry 30 seconds or until sauce boils and thickens.Return beef and any accumulated juices to the wok; heat through.Serve over pasta. Garnish is desired.