Step 1. Bring 2 quarts water to a boil in a saucepan. Add the vermicelli; cook for 3–4 minutes. Drain and rinse noodles under cold water; set aside. Halve shrimp lengthwise, and chill until ready to use. Working with 1 sheet of rice paper at a time, dip in a shallow dish of warm water until pliable. Lay rice paper on a dry surface, and blot away excess water.
Step 2. Place 4 shrimp halves on the lower center of rice paper. Top with 1/4 cup cooked noodles, some lettuce, 3–4 mint leaves, and 2 tablespoons bean sprouts.
Step 3. Fold in sides of rice paper toward center, and roll up wrapper away from you into a tight log. Repeat with remaining ingredients. Cover with plastic wrap until ready to serve. Slice rolls in half, using a slightly wet knife.