Divide the lettuce, bean sprouts, cucumber, mint, and basil among four large soup or pasta bowls. If working ahead of time, cover each bowl with damp paper towels and refrigerate.
Set peanuts aside. Make 1 recipe nuoc cham and refrigerate.
Bring a medium potful of water to a rolling boil. Add the rice vermicelli and, stirring often, cook them until the strands are soft and white, but still resilient, 3 to 5 minutes. Don't be tempted to undercook them, as they must be fully cooked to absorb the flavors of the dish. Rinse them in a colander under cold water just until they're cool and the water runs clear. Let the noodles drain in the colander for 30 minutes, and then set them aside for up to 2 hours, unrefrigerated.
Follow the directions for one of the recipes (Vietnamese Lemongrass Shrimp, Vietnamese Grilled Pork, or Vietnamese Stir-Fried Vegetables). These toppings can be served hot or slightly cooled.
Remove the salad bowls from the refrigerator 20 to 30 minutes before serving. The greens and bowl should be cool, not cold. Fluff the noodles with your fingers and divide them among the prepared salad bowls.
Put the cooked topping on the noodles and garnish each bowl with the peanuts and cilantro.
Pass the nuoc cham at the table. Each diner should drizzle about 3 tbsp over the salad and then toss the salad in the bowl a few times with two forks or chopsticks before eating.