01 - In a medium mixing bowl, combine the softened cream cheese, sour cream, lemon juice, chopped dill, salt, and black pepper. Stir until the mixture is smooth and well blended.
02 - Pat the diced cucumber dry thoroughly with a paper towel to remove excess moisture. Gently fold the cucumber into the cream cheese mixture until evenly distributed.
03 - Lay each flour tortilla flat on a clean work surface. Divide the filling evenly among the four tortillas, spreading it in a thin, even layer all the way to the edges.
04 - Roll each tortilla up tightly into a firm log shape, keeping the filling snugly enclosed 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 using a sharp chef's knife.
07 - Arrange the pinwheels on a serving platter, garnish with fresh dill sprigs if desired, and serve chilled.