Line a baking sheet with foil or a silpat and place in the freezer to chill.
Meanwhile, combine walnuts, cherries, ginger and sea salt in a bowl and set aside.
Break chocolate into pieces and place in a double boiler or a heatproof bowl over simmering water. Stir frequently with rubber spatula until chocolate is completely melted, about 5-6 minutes.
Stir in half of the fruit and nut mixture then spread onto chilled baking sheet. Use the spatula to shape a rough rectangle.
Sprinkle on the remaining fruit and nut mixture and place in the refrigerator to chill.
Cool completely, at least 60 minutes, then break into pieces.
Serve immediately or store in a Zip-loc bag in the refrigerator.
Notes
Feel free to mix and match the toppings. This is also delicious with crushed pistachios, dried cranberries or freeze-dried raspberries!