1. Preheat the oven to 350 degrees. Mist two 12-cup mini muffin tins with cooking spray. In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, ginger, cinnamon, allspice and salt.
2. In a small bowl, whisk together 1/2 cup water and the oil, vinegar and vanilla extract. Pour the mixture into the large bowl and stir to combine. Fill 20 muffin cups about 2/3 full with the batter.
3. Bake 12 minutes or until cooked through. Transfer tins to a wire rack and let cool 5 minutes; turn cakes out onto the rack.
4. Whisk together the confectioners' sugar and 2 tablespoons water. While the cakes are still slightly warm, drizzle the glaze over each and top with a large pinch of the candied ginger.