Butterfly chuck steak to less than 1 cm thick. Pound very thin. Grate, or very finely mince onion. Mix with garlic, ginger, juice and chile powder. Place mixture in non-reactive pan or dish large enough to hold meat in one layer. Place meat in mixture and turn to coat. Set aside to marinate 1 hour at room temperature, or overnight in fridge. French-cut the green beans, and cut carrot into thin strips. Broil meat close to the flame, 2-3 minutes per side. Remove to a platter and set aside for the juices to settle, 5 to 10 minutes. Meanwhile, broil the beans, carrot and green onion until limp and charred in spots, about 5 minutes. Remove and cut into 3 cm sections. Arrange lettuce on plates. Top with meat and vegetables, and sprinkle with mint. Serve with tortillas and peanut sauce.