In a medium mixing bowl, combine softened cream cheese, mayonnaise, dill, chives, garlic powder, and lemon juice. Mix until the consistency is smooth and well-incorporated.

Season the mixture with salt and black pepper according to preference.

Using a sharp bread knife, remove the crusts from all eight slices of bread.

Spread an even layer of the herbed cream cheese mixture onto one side of each bread slice.

Layer the cucumber slices in an overlapping pattern on four of the bread slices.

Place the remaining four bread slices on top, cream cheese side down, to close the sandwiches.

Cut each sandwich diagonally twice to create four small triangles, or once to create two rectangles, and serve immediately.