Mix together the butter, dill and a squeeze of lemon juice. Season with salt and pepper, then spread onto the 8 slices of bread. Place a slice of smoked salmon and some sliced cucumber on top of 4 pieces of bread and top with the remaining slices of bread.
Trim away the crusts and cut each into 4 triangles. Arrange on an elegant platter with some wedges of lemon for decoration.
