In a mixing bowl, combine the softened cream cheese, chopped dill, chives, lemon juice, salt, and pepper. Mix until smooth and well combined. Adjust seasoning to taste.

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

Lay out the slices of bread on a clean surface. If desired, lightly spread butter on one side of each slice to prevent the bread from becoming soggy. Spread a generous layer of the herbed cream cheese mixture onto each slice of bread. 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, to form sandwiches.

Using a sharp knife, carefully trim off the crusts from each sandwich. Cut each sandwich into quarters or thirds to create small, elegant tea sandwiches. Arrange them on a serving platter and garnish with additional fresh dill or chives if desired.