Start by thinly slicing the cucumber. For best results, use a mandoline or a sharp knife to ensure even slices. Place the cucumber slices on a paper towel to absorb any excess moisture.

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

Spread a thin layer of butter on each slice of bread (if using). Then, spread the cream cheese mixture evenly over the bread. Arrange the cucumber slices on top of the cream cheese, covering the bread completely.

Place another slice of bread on top to form a sandwich. Using a sharp knife, carefully cut off the crusts and slice the sandwich into smaller rectangles or triangles. Serve immediately or chill until ready to serve.