Mince the onion.

Heat 1 tsp of vegetable oil in a pan over medium heat. Add the ground beef and pork mix and cook until the meat changes color. Add the minced onion and sauté until softened. Stir in the sake, salt, ketchup, and Worcestershire sauce, and cook until the liquid evaporates. Remove from heat and let cool.

Place a spring roll wrapper with a corner facing you. Add 1/6 of the meat sauce and 1/6 of the pizza cheese near the bottom corner. Roll tightly, sealing the edge with the flour-water mixture. Repeat for all wrappers.