Half the oil from the canola oil should be added to a heavy skillet over medium heat. Once the skillet is hot, add the napa cabbage for 8-10 minutes and stir until the liquid has evaporated.
Mix in the carrots, garlic, and bamboo shoots. Cook for 1 min, stirring, before adding the mirin, soy sauce, and sesame oils. Let the filling cool completely.
Combine cornstarch and two tablespoons water.
Spread the spring roll wrapper on a flat surface. Apply cornstarch slurry to the edges to moisten. Add about 2 tablespoons filling and fold in the ends.
In a dutch oven, heat 3 inches oil to 325°F. Once the oil is heated to 325°F, fry the spring rolls in oil until golden brown (around 2-3 minutes).