Put the cucumber strips in a shallow glass or ceramic bowl. In a small bowl, mix together the mustard, vinegar, sugar and dill. Season well with salt and pepper, then pour over the cucumbers. Leave to stand for 5 minutes.
Cut the tortillas in half and lay on a board or work surface. Spread 1 tablespoon crème fraîche over each tortilla half.
Divide the smoked salmon pieces between the tortillas and top with the cucumber mixture. Add a little salt and pepper, if liked, and roll up each tortilla to form a cone around the filling. Secure each cone with a cocktail stick, if liked.