Soak the rice noodles in fairly hot water (about 120 degrees, just too hot to touch) for 10 to 20 minutes, or until soft.
2. Meanwhile, prepare the other ingredients.
Steam or simmer the shrimp over or in boiling water for 3 minutes or until pink.
Run them under cold water for a few seconds to stop the cooking, then peel and cut into two slices each.3.
Have all the ingredients in one place; you'll also need a bowl of hot water (110 to 120 degrees) and a clean kitchen towel.
Put a sheet of rice paper into the water for about 10 seconds, just until soft (don't let it become too soft; it will continue to soften as you work).
Lay it on the towel.
4. In the middle of the rice paper, lay 2 or 3 shrimp and about a quarter each of the carrots, noodles, mango, scallion, and cucumber.
Do not overfill.
Top with mint and cilantro; don't skimp on the herbs.
5. Working quickly, roll up the rice paper, keeping it fairly tight.
Now roll the rice paper roll in a sheet of plastic wrap, again making it tight.
Fold over the last bit of plastic wrap in the opposite direction, forming a tab that will make it easy to unwrap.
Twist ends and serve or store, refrigerated, for up to a day.6.
Make the dipping sauce.
Combine lime juice, fish sauce, garlic, chili and sugar and stir.
Serve or store, refrigerated, for up to a day.7.
To serve: Use a sharp knife to trim the ends of each roll.
Serve whole or cut into one-inch sections.
Serve with the dipping sauce.