Preparation

1. With a sharp knife or vegetable peeler, partially peel the cucumber lengthwise to create stripes. Thinly slice into 32 rounds which is easily done with a mandolin if available. Place the slices in a single layer onto a clean, dry dishcloth or paper towel then blot with an additional towel to remove excess moisture. Sprinkle the slices lightly with salt and pepper.
2. Lay the slices of bread side by side onto a cutting board. Divide the herbed cheese into 4 portions, then each portion in half again and top each bread slice with the cheese and spread from crust to crust in a thin, even layer. Then top each slice of bread with 4 slices of cucumber in a single layer, Top half of the bread slices with about 1/4 cup of the watercress leaves. Top with the other cucumber bread and press lightly.
3. With a serrated bread knife, cut off the crusts, then cut the sandwiches into quarters on the diagonal to create small triangles. Place onto serving plate or cover with a slightly damp paper towel and plastic wrap for up to 8 hours.