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

Wash the cucumber and slice it thinly. For extra crispness, place the slices on a paper towel to absorb any excess moisture.

If using butter, lightly spread it on one side of each bread slice. Spread a generous layer of the herbed cream cheese mixture onto the unbuttered side of four bread slices. Arrange the cucumber slices evenly over the cream cheese. Top with the remaining bread slices, cream cheese side down.

Using a sharp knife, trim the crusts off the sandwiches for a clean, elegant look. Cut each sandwich into quarters or smaller rectangles for tea sandwiches. Arrange them on a platter and serve immediately.