Once ready to assemble, pour warm water into a bowl or a round cake pan. Set aside.
To make the rice paper roll, dip and soak 1 rice paper wrapper in the warm water for 5 seconds. Then, place rice paper wrapper onto a clean bench or a large plate.
Now the filling: in the centre of the wrapper, slightly further down, place 3 prawns, a couple of cucumber matchsticks, 2 or 3 mint leaves and a small pinch of vermicelli noodles (about 1 - 2 tbsp). (note 1)
Fold in the bottom of the rice paper, covering the filling, then fold in left and right of the rice paper. Finally, roll upwards, firmly. Kind of like wrapping a spring roll or a tiny burrito.
Repeat for the rest of the rolls.