Cook bacon in the microwave on a paper towel-lined microwave safe plate until crispy, about 4 minutes.
Meanwhile, stir together tuna, Dijon mustard, horseradish, relish, and red onion. Season with paprika and pepper. Divide this mixture between the hoagie buns. On each sandwich, place 1/2 an avocado, 1/2 a tomato, 1 slice provolone cheese, 1 lettuce leaf, and 2 slices bacon.
