For the rice paper summer rolls: Dip a sheet of rice paper a 1/3 of the way into a bowl of hot water for about 2 seconds. Turn it and dip remaining section, then lay on a damp towel.
Working on the bottom 1/3 of rice paper, spread a bit of lettuce, noodles, carrots, herbs, and pork and/or shrimp. Fold up bottom edge to cover, then fold in the sides. Roll tightly. Continue with remaining ingredients.
For the dipping sauce: Combine fish sauce, sugar, ginger, chile-garlic paste, and about 1/4 cup water. Taste and adjust seasoning, adding salt and pepper, if necessary.
Serve rolls right away, or refrigerate, lightly covered, up to 2 hours. Cut each roll into 2 or 3 pieces, then serve with dipping sauce and lime wedges.
Summer Roll Salad: Omit rice paper; use about 6 cups torn lettuce leaves, 3 cups noodles, and 1 1/2 cups carrots; other ingredients can remain the same. Divide lettuce among 4 plates, then top each with a 1/4 of the noodles, carrots, herbs, and pork or shrimp. Drizzle the dipping sauce over all, and serve with lime wedges.