Combine hoisin sauce, vinegar and water in a bowl. Transfer to a serving bowl. Top with peanuts and chilli.
Place noodles in a bowl and cover with boiling water. Stand for 5 minutes or until softened. Drain well. Fill a large bowl with warm water. Using one sheet of rice paper at a time, dip into water for 10-20 seconds or until slightly softened. Place on a flat surface. Place 2 coriander leaves on middle of rice paper. Top with noodles, chicken, carrot, mandarin and cucumber. Fold the side closest to you over filling. Fold sides over towards centre and roll up, enclosing filling. Place on a platter. Repeat with remaining sheets and filling to make 15 in total. Serve with the sauce.