Heat oil in deep fryer to 375. Work with 6 wonton skins at a time. Keep remainder well wrapped in waxed paper and draped with lightly dampened towel. Place a wonton skin on work surface and set a cannoli tube diagonally across center of it. If you don't have a cannoli tube, form a tube with some aluminum foil. Bring sides of skin up over tube. Seal overlapping tips with a dab of water. Form wonton skins around remaining 5 tubes. Cook, 2 tubes at a time, seam side down in hot oil, for 30 seconds or just until golden. Remove with tongs and drain on paper toweling. While shells are still hot, gently push them off tubes with a small metal spatula and your fingers. Repeat with remaining skins and be sure tubes cool completely before wrapping with skins.

Filling: Combine ricotta, confectioners' sugar, Vanilla and chocolate. Cover and chill 2 hours or overnight. To serve: spoon filling into cannoli shells. A pastry bag will be very helpful here, or cut a corner off of a sandwich bag and squeeze the mixture out of it. Dip each end of filling in pistachios. Arrange on serving plate. Sift additional sugar over each and garnish with mint sprigs.