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. Pat the slices dry with a paper towel to remove excess moisture if desired.

Lay out the slices of bread on a clean surface. Lightly butter one side of each slice if desired. 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 trim the crusts off the sandwiches for a more elegant presentation. Cut each sandwich into quarters or smaller triangles. Arrange them on a platter and serve immediately.