01 - In a medium mixing bowl, combine the softened cream cheese, sour cream, lemon juice, chopped dill, salt, and black pepper. Stir with a spatula until completely smooth and well blended.
02 - Pat the finely diced cucumber dry with paper towels to remove excess moisture, then gently fold it into the cream cheese mixture until evenly distributed.
03 - Lay each flour tortilla flat on a clean work surface. Divide the cucumber-cream cheese mixture evenly among the four tortillas, spreading it in a thin, even layer all the way to the edges.
04 - Roll each tortilla up tightly from one edge to form a compact log, keeping the filling tucked in as you roll.
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, discarding the uneven ends if desired.
07 - Arrange the pinwheels cut-side up on a serving platter, garnish with fresh dill sprigs, and serve chilled.