Preheat the fryer. Spread 1 tablespoon of the melted chocolate over each wonton, leaving a 1/2 inch border. Place the banana on the bottom edge of each wonton. Lightly wet the edges of each wonton with the butter. Fold in the ends toward the center about 1/4-inch. Then, beginning at the bottom, roll up the wonton securely, pressing to close. Fry until the bananas are golden, about 3 minutes, stirring constantly for overall browning. Remove and drain on paper towels. Sprinkle with the powdered sugar. To serve, place a scoop of the ice cream in the center of each shallow bowl. Lay two of the fried bananas next to each scoop of ice cream. Drizzle with the chocolate sauce.