Here's how you can add the wipe command to your right-click menu using Nautilus-actions. This will enable you to securely delete one or more files/folders without having to use the command line. To install Nautilus-actions, enter the following in your terminal.
Next, copy everything you see in the following two windows.
When your done click the OK button and close Nautilus-actions. Now you should see 'Wipe selected' command appear when you right-click on a file or folder. You will not be asked for confirmation when your wiping a file/folder so use with care.