In a mixing bowl, combine the softened cream cheese, chopped dill, chives, lemon juice, salt, and pepper. Mix until smooth and well combined. Taste and adjust seasoning if needed.

Wash the cucumber and slice it thinly. For best results, use a mandoline slicer to achieve even, paper-thin slices. Pat the slices dry with a paper towel to remove excess moisture.

Lay out the slices of bread on a clean surface. If desired, lightly butter each slice to add a layer of flavor and prevent sogginess. 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 the crusts off the sandwiches for a clean, elegant look. Cut each sandwich into quarters or smaller rectangles for tea-time finger sandwiches. Arrange them on a platter and serve immediately.