1. Preheat broiler. Place the chicken breasts on a broiler pan and brush liberally with garlic oil. Broil until cooked right through and golden brown, turning once during cooking to brown both sides. Let cool while you prepare the salad.

2. Arrange the lettuce leaves in a serving dish, and then sprinkle with the chopped green onions, diced cucumber, sliced oyster mushrooms, and water chestnuts.

3. Dressing: put the fish sauce, lime juice, garlic, sugar, and shredded red chilies in a small saucepan. Place the pan over a low heat and cook very gently, stirring all the time until the sugar has dissolved. Remove from the heat.

4. Cut the cooked chicken into strips and arrange them on top of the salad. Cover with the warm dressing. Serve the salad warm.