Prepare a cookie sheet with parchment paper or waxed paper. Place semisweet chocolate in a microwave-safe bowl and melt at 30% power for 30 seconds at a time, stirring between each melt. Pour chocolate onto cookie sheet and spread thin with a spatula. Scatter cherries, pistachios, almonds, and candied ginger evenly over the chocolate. Place white chocolate in a microwave-safe bowl and melt at 30% power for 30 seconds at a time, stirring between each melt. Use a spoon to drizzle the white chocolate over the fruit-and-nut-filled bark. Refrigerate the bark for about 20 minutes or until firm; break into pieces. Store bark in an airtight container at room temperature or in the refrigerator.