In a bowl, mix cream cheese, lemon juice, dill, and red onion until smooth.

Lay one tortilla flat and spread a thin, even layer of the cream cheese mixture over the whole surface.

Arrange smoked salmon in a single layer on top.

Roll the tortilla up tightly and wrap it in plastic wrap.

Chill for at least 1 hour to firm up.

Slice into 1-inch pinwheels right before serving.