Cut the rice paper into bite-size pieces.
Slice the fish cake, onion, and green onion.
Heat oil in a pan and stir-fry the onion, green onion, and fish cake.
Add tteokbokki sauce (gochujang, chili powder, sugar, soy sauce, water) and bring to a boil.
Add the rice paper and quickly stir-fry together.
Top with mozzarella cheese and sesame seeds to finish.