1. Arrange the chicken, cucumber, carrots, scallions and bean sprouts on a platter. Place the mint and cilantro on a separate plate, and the peanuts in a small bowl alongside. Arrange the lettuce on a separate platter.
2. To make the nuoc cham, whisk together lime juice, fish sauce, sugar and water together until the sugar is fully dissolved.
3. Encourage your dining companions to make their own lettuce wraps that suit their own tastes. I think the best way to start is to pile everything in a large lettuce cup and drizzle the dressing on top – but to each their own! Garnish with lime slices and serve.