On a cutting board, with a paring knife, slice each frozen lime fruit bar lengthwise into four "logs," then cut logs into cubes.
Place frozen lime fruit bar cubes into a small crystal glass or cup and sprinkle lightly with fresh lime juice. Place glass or cup into freezer until just before serving. Shave dark chocolate bar with a potato-peeler and save shavings in a Tupperware container in a cool place.
Just before serving, add a healthy dollop of the Cool Whip topping to each dessert. Drizzle with lemoncello liqueur. Top-off with dark chocolate shavings. Enjoy.