Place chocolate in a glass or stainless steel bowl. In a saucepan over medium heat, bring wine, crème de cacao, crème de cassis and salt to a simmer. Add heavy whipping cream and return to a simmer. Remove from heat.
Pour hot cream mixture over chopped chocolate and stir until smooth. Chill in refrigerator for 2 to 3 hours or until firm. Fill a pastry bag with the cooled chocolate. Pipe table grape-sized mounds onto a sheet tray lined with parchment paper. Refrigerate 1 hour, then roll each mound between your palms to form perfect spheres. Refrigerate 15 minutes to set centers before dipping.
Melt coating chocolate in a stainless steel bowl over simmering water, stirring frequently, until smooth. Remove from heat and allow to cool to room temperature. Using two forks, submerge centers into coating chocolate and remove. Place on a wire rack to set slightly, then roll on the wire rack while still wet to form spikes (see Chef’s Note). Refrigerate approximately 15 minutes to harden. You also can freeze truffles in an airtight container for up to a month.
When all truffles are dipped, rolled and cooled, toss in cocoa powder to coat. If frozen, allow truffles to come to room temperature before final coating.