Step #1 Blend all ingredients for the creamed butter to a fine, soft, spreadable consistency (salt & pepper to taste).
Step #2 The cucumber must be cut as thin as possible, using a mandolin or a food processor/blender fitted with a metal blade.
Step #3 Very lightly salt the slices & leave them to drain in a colander, lightly weighted with a plate, for 2 hrs or so, pressing from time to time to get rid of the excess juices.
Step #4 Combined the slice & drained cucumbers with the olive oil, lemon juice & sugar & dredge through the freshly ground white pepper (do not add more salt).
Step #5 Butter 10 slices of bread with creamed butter.
Step #6 Layer the cucumbers on the butter bread & then press a second slice of bread firmly on to the top of the sandwich, crust & cut into appropriate shapes (should make 30 fingers or 40 squares or quarters).