Preheat an oven to 350 F. Lightly butter the wells of a miniature cheesecake pan.
To make the crusts: In the work bowl of a food processor, combine the chocolate wafers, 1 tablespoon sugar and the salt and pulse until the mixture is finely ground.
Transfer the mixture to a small bowl and add the melted butter. Stir to combine. Divide the mixture among the 12 wells in the prepared cheesecake pan and press evenly into the bottoms.
Bake until the crusts are set and golden brown around the edges, 10 to 12 minutes. Transfer the pans to a wire rack and let cool completely.
Reduce the oven temperature to 250 F.
To make the filling: In the bowl of an electric mixer fitted with the flat beater, combine the cream cheese, the 1/3 cup sugar and the pinch salt and beat on low speed until smooth, 8 to 10 minutes, scraping down the sides of the bowl often.
Beat in the egg slowly and scrape down the sides of the bowl after adding it. Pour in the melted chocolate and Kahlua and beat until completely blended and no streaks of white remain, about 1 minute. Spoon the filling into the crusts, dividing it evenly among the 12 wells.
Bake until the filling is set, 20 to 25 minutes. Transfer the pan to a wire rack and let cool to room temperature. Cover with plastic wrap and refrigerate for at least 4 hours before removing the cheesecakes from the pan.
Makes 12 miniature cheesecakes.