In a small bowl, stir together the brandy and espresso powder; set aside. In a food processor, pulse the wafers until finely ground; set aside 1/4 cup crumbs. Transfer the remaining crumbs to a medium bowl. Stir in the espresso mixture. Beat in the butter and salt until combined.
Using your hands, roll a scant tablespoon of the dough into a 1-inch ball and drop onto a small cookie sheet lined with wax paper. Repeat with the remaining dough. Freeze the cookies until firm, about 15 minutes.
Roll the cookies in the reserved crumbs, rounding them with your palms if they have flattened on the bottom. Store in the refrigerator.