Prepare all vegetables and toppings, and set them in separate bowls for easy assembly.
Fill a shallow dish with warm water. Dip one rice paper wrapper into the water for 10-15 seconds, just until soft and pliable.
Place the softened wrapper on a clean, damp surface. Layer vegetables, herbs, avocado, and rice noodles (if using) in the center.
Fold the bottom edge over the filling, then fold in the sides, and roll tightly like a burrito. Repeat with remaining wrappers.
To make the Thai peanut sauce, whisk all sauce ingredients together in a bowl until smooth. Add more water to reach desired consistency.
Serve salad rolls with peanut sauce on the side or drizzled on top.