The title and content don't match out. Do you want to delete a virtual hard disk image from a virtual machine, or do you want to simply get rid of a virtual machine? The latter can be done from the main VM window, while the former can be achieved by first editing the VM configuration to have the desired hard disk image removed from the profile, then finding the said image file via Finder and deleting it (make note of its location so you know where to look).
