01 - In a medium bowl, blend together the softened cream cheese, sour cream, lemon juice, chopped dill, salt, and black pepper until smooth and well combined.
02 - Pat the diced cucumber dry with a paper towel to remove excess moisture, then gently fold it into the cream cheese mixture.
03 - Lay each tortilla flat on a clean work surface. Spread approximately one quarter of the cucumber-cream cheese mixture evenly over each tortilla, extending all the way to the edges.
04 - Roll each topped tortilla tightly into a firm log shape, keeping the filling evenly distributed.
05 - Wrap each rolled tortilla tightly in plastic wrap and refrigerate for at least 20 minutes to allow the filling to firm up and hold its shape when sliced.
06 - Unwrap each chilled roll and slice crosswise into 1/2-inch thick pinwheels using a sharp chef's knife.
07 - Arrange the pinwheels on a serving platter, garnish with fresh dill sprigs if desired, and serve chilled.