Combine water, hoisin sauce and vinegar in small bowl. Heat large nonstick skillet over medium-high heat until hot. Brush skillet with oil. Add cucumber, bell pepper and green onions; stir-fry 1 minute. Stir in noodles, 1/2 of cilantro and 1/2 of hoisin mixture. Remove.
Heat same skillet over medium-high heat until hot. Place beef steaks in skillet; cook 2 to 4 minutes, turning once. Do not overcook. Add remaining hoisin mixture; turn steaks to coat. Serve over noodles. Sprinkle with remaining cilantro.