Slice the steak as thin as possible, diagonally across the grain. Combine with the lime juice, gingerroot, garlic, hot sauce, sugar, and basil, and marinate at least 3 hours in the refrigerator. Line a platter with lettuce leaves, and scatter with the onion and cucumber slices and the bean sprouts. Mix the steak and marinade with the pasta, and mound on the platter, over the vegetables. Garnish with tomato, lime, and basil.