SecureDelete Lite is a free application service available globally via Services and contextual menu. It allows you to secure delete on a per-item basis from anywhere, rather than having to secure empty your entire Trash.
Simply right-click on any selected item, or items, on your screen and choose to Secure Delete. Plus, with the optional "Expanded View" you can always modify your selections - should you suddenly change your mind.
- OS X 10.7 or later