Typically, Vietnamese spring rolls are made with rice vermicelli, which are very thin rice noodles. Various manufacturers will call them thin rice noodles, rice sticks, or maifun. One important thing to note is that the cooking time of the noodles varies across brands.
Rather than using pastry with a rolling technique, they have a more doughy texture. In Austria and Germany, deep-fried spring rolls are called Frühlingsrolle, while the Vietnamese salad rolls are called Sommerrolle ("summer roll").
Place 1/3 cup filling in the middle of the spring roll pastry sheet. Dip 1 finger in a small bowl of water and run along the edge of the spring roll pastry sheet. Fold in the sides to meet in the middle over the filling. Fold up the bottom point over the filling, then tuck to tighten the roll and roll the wrapper towards the top point.