Mix first 6 ingredients in small bowl. Place steak in large resealable plastic bag or glass dish. Add marinade; turn to coat well. Refrigerate 15 minutes.
Place salad greens on large serving platter. Set aside.
Heat large skillet on high heat. Add steak and marinade; cook and stir 2 to 3 minutes or until steak is no longer pink.
Arrange steak over salad greens. Top with bell pepper strips and green onions. Serve with guacamole and tortilla chips, if desired.