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

Using a sharp knife or a mandoline slicer, thinly slice the cucumber into even rounds. For extra crispness, lightly salt the cucumber slices and let them sit on a paper towel for 10 minutes to draw out excess moisture. Pat them dry before using.

If desired, lightly butter one side of each slice of bread to add a rich flavor and prevent sogginess. Spread a generous layer of the cream cheese mixture onto the unbuttered side of 4 slices of bread. Arrange the cucumber slices evenly over the cream cheese, slightly overlapping if needed. Top with the remaining slices of bread, buttered side out.

Using a sharp knife, carefully trim the crusts off the sandwiches for a clean, elegant look. Cut each sandwich into quarters or smaller rectangles to create bite-sized tea sandwiches. Arrange them on a platter and garnish with additional fresh dill or chives if desired.