Mix the drained tuna, red onion, and mayo.
Add sea salt, black pepper, and a squeeze of lemon to taste.
Cut the cucumber thinly using your mandolin. You'll need about 8-10 strips.
Dry the slices off on both sides with a paper towel.
Place the cucumber slices next to each other, overlapping slightly.
Top with cream cheese 4/5th of the way.
Place the tuna mixture on top of the cream cheese, leaving space above and below so as not to overstuff.
Sprinkle the Tabasco and lemon juice over the tuna mixture.
Roll the cucumber tuna strips up tightly into plastic wrap.
Place the roll in the freezer for 15-20 minutes.
Remove from the freezer and slice into similar-sized pieces with a sharp knife.
Use the flower cookie cutter to shape the flowers out of the snack cucumber.
Top the rolls with the flowers and a basil leaf (sriracha mayo would be delish, too).
Serve right away.