In a small bowl, mix the softened cream cheese, chopped dill, lemon juice, salt, and pepper until well combined.

Using a sharp knife or a mandoline, thinly slice the cucumber. For extra crispiness, lightly salt the cucumber slices and let them sit for 10 minutes, then pat them dry with a paper towel.

Lay out the slices of bread on a clean surface. If desired, lightly butter one side of each slice. Spread a generous layer of the cream cheese mixture onto the unbuttered side of each slice. Arrange the cucumber slices evenly over the cream cheese on half of the bread slices. Top with the remaining slices of bread, cream cheese side down.

Using a sharp knife, carefully cut off the crusts from each sandwich. Then, cut each sandwich into quarters or halves, depending on your preference. Arrange them on a platter and serve immediately.