Preheat oven to 120ºC ; line a large cookie sheet with parchment paper. In a cup, dissolve the espresso powder in the water. Stir in the creme de cacao and vanilla extract; cool to room temperature. In a small, deep bowl with an electric mixer on high speed, whip the egg whites until foamy. Gradually beat in all but 2 tablespoons of the sugar, 1 tablespoon at a time, alternating with a scant quarter teaspoon of the espresso mixture at a time. Continue beating until the mixture forms stiff peaks. In a small bowl, stir together the cocoa with the remaining 2 tablespoons sugar. With a rubber spatula, quickly but gently fold cocoa into the meringue, being careful to avoid deflating the egg whites. Drop the meringue by teaspoonfuls onto the cookie sheet. Bake for 25 to 30 minutes, or until they are firm on the outside, but still a bit soft on the inside. While hot, remove the kisses with a spatula to a wire rack. Cool completely; store in a container with a loose fitting lid.