In a small bowl, combine the garlic, chillies, lime juice, water, soy sauce, sugar and 2 tablespoons oil.
In a serving bowl combine the lettuce, bean sprouts, carrot, basil, mint and coriander and toss. Preheat the grill.
Rub the steak with the remaining 1 tablespoon oil and salt and pepper then grill about five minutes a side or until browned but still medium rare within. Let rest a few minutes and then cut into 5mm slices.
Lay the steak slices over the salad and drizzle the garlic dressing over the top. Serve hot.