For the taco shells: Heat oil to 375 degrees F. Place 1 wrapper into each slot of a taco/tostada fry basket and fry until golden brown. Repeat with the remaining wrappers. Let the shells cool.
For the dressing: Mix all ingredients for dressing in a small bowl and chill.
Prepare remaining guacamole ingredients and add to a medium bowl. Gently fold together using a rubber spatula or wooden spoon until everything is evenly distributed, but you don't want a puree. Maintaining the integrity of the vegetables is critical as it adds a great texture and visual appeal to the dish. Season with salt to taste before serving.
Place some of the tuna and daikon into a taco shell. Drizzle with dressing. Top with a bit of guacamole. Repeat with remaining ingredients. Serve immediately.