In a skillet, heat the oil on medium high. Add the mushrooms and sauté until golden brown and tender, about 5 minutes. Season with salt and pepper. Let cool.
In a saucepan, boil a few cups of water. Fill a bowl with about 2 cups of warm water. Boil the vermicelli noodles for 1 minute, drain them, and put them in the warm water until they’ve softened, about 15 minutes. Drain them and set aside. Mix the carrots with the sugar and let stand for 10 minutes.
Divide the noodles, mushrooms, carrots, shrimp, and bean sprouts into 16 equal portions. Lay a kitchen towel on your work surface. Fill a pie plate or bowl with warm water and immerse one sheet of rice paper in it for a few seconds, just until it’s soft and flexible. Put the rice paper on the towel and let it rest until it’s more pliable, about 30 seconds. Put half a lettuce leaf on the bottom two thirds of the rice paper, leaving a 2 inch border on the bottom edge. Put one portion of noodles on the bottom of the lettuce leaf, top with a portion of mushrooms, carrots, shrimp, and bean sprouts. Put a few mint and cilantro leaves on top.
Immersing rice paper in warm water softens it. Work with one at a time, be gentle and have extra on hand since some will break.
Fold the bottom border over the filling ingredients, which should be cool and well drained.
Fold the bottom 2-inch border of the rice paper over the filling. Fold over again to enclose the lettuce leaf. Fold in the right and left edges. Place 2 chives on the fold at the top of the filling, and continue rolling up the paper. Transfer the spring roll, seam side down, to a platter and cover with a damp paper towel. Repeat with the remaining sheets of rice paper and filling ingredients.
Tuck two chives on top and finish folding. Cover the spring rolls with damp paper twoels and wrap tightly in plastic until serving time.
To serve, slice the rolls in half at a sharp angle, if you like, and let people dunk in the dipping sauce.
These rolls can be made a day ahead. Cover them with a damp paper towel and wrap well in plastic before refrigerating them.