1/2 seedless cucumber, peeled and very thinly sliced (about 32 slices)
1/4 cup loosely packed fresh mint leaves, rinsed, spun dry, and chopped fine
1/4 cup unsalted butter, room temperature
1/4 cup cream cheese, room temperature
16 slices best-quality white bread
Salt to taste
Place cucumber slices between layers of paper towels to remove excess moisture.
In a small bowl, combine mint, butter, and cream cheese; spread on one side of each slice of bread. Lay cucumber slices onto the buttered side of 8 slices of bread. Sprinkle with salt. Top with the remaining slices of bread, buttered side down.
Carefully cut the crusts from each sandwich with a sharp knife. Cut the sandwiches in half diagonally and then cut in half again.