Stir together ice cream (reserve pint container), extract, and 1/2 cup crushed candy in a bowl until combined.
Transfer mixture to pint container and freeze until just firm enough to scoop, about 1 hour.
Working very quickly, scoop ice cream onto flat sides of 8 wafers (1 scoop per wafer), then top with remaining 8 wafers, flat sides down. Wrap each sandwich individually with plastic wrap and freeze until firm, about 1 hour. Unwrap sandwiches and roll edges in remaining 1/2 cup crushed candy. Rewrap and freeze until firm, about 1 hour.