Drain tuna and add to a small mixing bowl.

Dice celery and add to tuna, along with lemon juice and mayo. Mix well and set aside.

Remove the core from peppers, then slice into 2-inch wide slices. Place these slices open-side up onto a plate.

Slice the ends off cucumber and then slice the cucumber into thirds. Using a mandoline slicer or a sharp knife, slice each cucumber chunk lengthwise into thin pieces. Place a skewer (or if the cucumber slice is small enough you may use a toothpick) through the bottom and top of each cucumber slice to serve as the sail.

Fill each bell pepper "boat" with tuna salad and then press the skewer of the sail through the pepper.

Slice tomatoes in half and place open-side down onto the tuna salad.

Serve with any remaining veggies on the side.