Begin by boiling water in a pot and then add your vermicelli noodles. Soak them for about 4-6 minutes until they are just tender but still firm to the bite. Once done, drain them in a colander and cut the noodles into 2-inch lengths to make them easy to handle when assembling the rice paper rolls.

In a shallow bowl, fill it with warm water. Take one rice paper sheet and dip it in the warm water for approximately 15-20 seconds, or until it becomes pliable and soft. Gently lift it from the water and let any excess water drip off before placing it on a damp work surface.

With the softened rice paper laid flat, start layering your ingredients in the center. Place a small handful of the prepared vermicelli noodles, followed by strips of fresh tuna, slices of avocado, matchsticks of cucumber, and a sprinkle of shredded red cabbage. Make sure not to overcrowd the filling for easier rolling.

Begin rolling the rice paper from the edge closest to you, carefully folding in the sides as you go. Aim to roll tightly enough to hold the filling securely but not so tight that it tears the rice paper. Make sure the seam is facing down once you finish rolling for a clean presentation.

In a small mixing bowl, combine equal parts of soy sauce and rice wine vinegar, around 2 tablespoons each. Add a teaspoon of sesame oil to introduce a nutty flavor. Whisk together until well combined, adjusting the proportions to your taste for a perfect tangy dipping sauce to accompany your fresh tuna rice paper rolls.

Arrange your completed fresh tuna rice paper rolls on a serving platter. For a delightful touch, sprinkle sesame seeds on top. Serve alongside the tangy dipping sauce, and enjoy the vibrant colors and fresh flavors of your homemade rice paper rolls as a delightful appetizer or light meal.