In a medium-sized mixing bowl, combine whipped cream cheese, sour cream or mayonnaise, and finely chopped dill. Mix until smooth and creamy, about 2-3 minutes. Add kosher salt.

Lay out eight slices of sandwich bread on a cutting board and spread the herbed cream cheese mixture on one side of each slice.

Rinse and slice the cucumber paper-thin using a mandolin or sharp knife. Layer cucumber slices over half of the prepared bread slices, slightly overlapping.

Place the remaining bread slices, spread-side down, on top of the cucumber-covered slices and gently press down.

Trim off the crusts using a serrated knife and cut the sandwiches into bite-sized pieces.

Arrange the sandwiches on a platter and garnish with fresh dill sprigs or cucumber slices if desired.