In Ghost Solution Suite 2.5 Console there was an option to perform a disk wipe by right clicking on a client system but this option is not currently in the 3.x product.
Although the option to perform a disk wipe is not built in to the GSS 3.x console a script to perform the same task could be set up and executed in automation from the 3.x console.
HOWTO9581 goes more in depth on Gdisk command line options but below steps could be used as a guideline to create a job with this task.
Below are the steps to create a Job that will run a script to run gdisk.
If your pe environment that is going to be used is 64bit then you will need to use Gdisk64.exe, the following also assumes that the win pe automation environment also us using M: to connect to your express share.
gdisk64 1 /diskwipe
Now there is a job on the server that can be assigned to clients to perform a disk wipe.