Soak noodles in boiling water in a large heatproof bowl for 5 minutes; stir to separate strands, then drain
Using scissors, cut noodles into shorter lengths
Place noodles in a large bowl; drizzle with 2 tablespoons of the dipping sauce
Add vegetables and herbs; toss to combine
To assemble rolls, place 1 sheet of rice paper in a medium bowl of warm water until just softened
Lift sheet from water carefully; place on a board covered with a clean tea towel
Place 1/3 cup of mixture across lower part of the wrapper, in a neat horizontal pile
Fold bottom end over, then sides and roll up tightly
Place on a platter. Repeat with remaining rice paper sheets and vegetable filling