Top each cheese covered slice with 2 slices each of prosciutto, 3 leaves of arugula, thinly sliced tomatoes seasoned with a pinch of salt. Place a completed layer a top another, making 2 stacks each 2 layers high.
Set the final trimmed bread slices in place, making 2 triple-decker sandwiches.
Thinly slice and salt the radishes.
Pierce a couple of thin slices of radish on each toothpick as you place 4 toothpicks in each sandwich.
Cut each sandwich into 4 equal parts, cutting the sandwich across evenly on each side.
The yield will be 8 triple-decker, square-shaped, "club" finger sandwiches, 2 per portion.