Step 1Break up any large pieces of crabmeat with a fork.
Step 2To make a lemon vinaigrette, combine the lemon juice and shallot in a small bowl. Whisk in the canola oil. Season with salt and pepper. Stir in the chives and chervil.
Step 3Pour the lemon vinaigrette over the crabmeat and gently stir with a fork until evenly coated.
Step 4Slice the cucumbers lengthwise into very thin strips. (A mandoline works best.) Slice the cucumber on one side until you reach the seeds, then turn the cucumber and slice the second side down to the seeds. Discard the center of the cucumber with the seeds. You will want about 6 strips of cucumber for each serving, or a total of 36 cucumber strips.
Step 5For each serving, lay the 6 cucumber slices out flat and squeeze a few drops of lemon juice from a wedge of lemon over each cucumber slice, then grind a little black pepper over the cucumber.
Step 6To assemble, measure one-third cup crab salad for each serving. Place a cucumber strip on a plate, then some of the salad onto the cucumber, then top with a second slice of cucumber, rippling and folding the cucumber in an attractive manner. Repeat using the remaining cucumber slices and crabmeat. Repeat this procedure for the remaining servings.