I am in the process of moving my tutorials and freebies from my website to my blog. These tuts have been posted at my website before.
Choose the stamp option in photoshop or paintshop.
Load the image and make a new layer.
Choose the "clone" or "stamp" brush.
Click the clone or stamp brush.
(left sample in Paintshop Pro)
Choose a fitting cut/crack brush. You can download such brushes for free at Devianart.com for example. (browse resources, application resources, brushes),
(Left Sample in Photoshop)
If you want a torn chainmail, click some skincolor in your image and stamp it on the chainmail (see skin trough the chainmail). If you want a cut in a tunic, click the chainmail and you see the chainmail under the tunic coming trough the torn tunic.
Left Sample of a cut in the chainmail
Sample of a cut in the tunic (on the chest).
and a few more samples