Season steak on both sides with salt and black pepper.
In a large skillet, heat neutral oil over high heat until hot but not smoking. Add steak and sear until brown, about 5 minutes per side for medium-rare. Transfer to a plate and cover with aluminum foil. Let rest.
In a large bowl, combine green onion, cucumber, tomato, avocado, cilantro, lime juice and olive oil. Toss well. Season with salt and black pepper.
Slice steak. Divide steak and salad evenly among four plates. Serve.