To make the cannoli shells: In large bowl, mix together the flour, cocoa powder, and salt and cut in the margarine until evenly blended. Then gradually work in the wine and water to form a compact dough. Cover the dough with plastic wrap and let rest at room temperature for an hour. On a lightly-floured surface, roll out the dough to 1/8-inch thickness. Cut out 5-inch-wide circles and cover. Re-roll the scrap dough to form more circles.
In a deep-fat fryer or heavy-bottomed saucepan, heat the oil to 350 degrees F. Wrap each circle onto a mold, sealing the two edges that overlap with a dab of water and by pressing together. Carefully immerse a few shells at a time, into the hot oil and fry until golden and crisp. Drain the shells on paper towels, let cool and remove the molds from the cannoli.
To make the filling: In a bowl, whip up the ricotta and sugar until creamy. Add the grated chocolate. Mix thoroughly. Using a piping bag, pipe the filling into each shell, starting at the middle and working out towards each end. Garnish the ends of each cannoli with sliced candied fruit and then dust the cannoli with icing sugar.