Thinly slice or grate the cucumber and pat dry. (I highly recommend using a mandolin for even slices.) Leave the cucumbers on some paper towels while you make the spread. This will help pull out some more moisture.
Remove the crusts from the bread slices. Since not all bread slices are the same size, stack them up in similarly sized groups of 4, and cut off the crusts. Then keep the groups together so your sandwiches don't have uneven tops and bottoms.
Add the cream cheese, mayo, and lemon juice to a medium mixing bowl. Beat together with a hand mixer until fluffy. Use a rubber spatula to fold in the herbs until evenly mixed. Season with salt and pepper to taste.
Spread the cream cheese mixture onto one side of each slice of bread. Then place the cucumber slices onto half of the bread slices (it's okay if they overlap a bit). Place the top bread slice onto the sandwich with the filling facing the cucumbers.
Enjoy these sandwiches as is, cut in half on the diagonal to make triangles, or cut into quarters to make 32 small squares. Serve immeditely.
Notes
Recipe yield will vary on how you cut (or don't cut) the sandwiches.
8 whole "big" sandwiches
16 triangle sandwiches
31 small square sandwiches
You can make the cream cheese spread by adding all of the ingredients into a food processor to save yourself the chopping step. Cover and pulse until smooth and evenly mixed (scraping down the sides of the bowl as needed). For the herbs, you will need 1 dill from one big sprig, 6-8 chives, and 4-6 sprigs of parsley.