In a small bowl, combine whipped cream cheese, sour cream (or mayonnaise), chopped dill, and kosher salt. Mix until smooth and creamy, about 2-3 minutes.

Spread a generous layer of the herbed cream cheese mixture on one side of each slice of sandwich bread.

Using a mandolin or sharp knife, slice the English cucumber thinly, aiming for about 1/8-inch thickness.

Lay half of the prepared bread slices cream cheese-side up and arrange the cucumber slices on top, slightly overlapping.

Trim off the crusts from each sandwich with a serrated knife for a neat appearance.

Cut each sandwich into quarters diagonally or rectangularly.

Transfer the cut sandwiches onto a serving dish, and optionally garnish with extra sprigs of dill or cucumber slices.