During the VR training tutorial, Raiden can practice slices on cardboard cutouts of enemies that are holding a female hostage. Cut the hostage's shirt just right to attack will remove her clothes.

In Denver while enroute to the World Marshal corporation's headquarters, you can find a pinup poster covered in police tape. Slice off the tape to reveal the full picture.

After rescuing the civilian hostages from the soldiers and chasing after them, you can slice in Blade mode to remove the civilian's clothes.