Clean the mushrooms and finely chop them into small cubes. Fry them in the sesame oil, then add the soy sauce and saké. When the excess water has evaporated, remove from the heat.
Chop the chilli peppers into the same size chunks as the mushrooms and mix everything together.
Moisten the sheets of rice paper and fill them with the mixture, forming squares of the same size.
Sprinkle chilli and mushroom pieces on top and serve.