You can use vmware-vdiskmanager in a Terminal. (/Applications/VMware\ Fusion.app/Contents/Library/vmware-vdiskmanager}
Syntax: vmware-vdiskmanager -r sourceDisk.vmdk -t 0 destinationDisk.vmdk
The -t option can be 0 or 1, 0 being a monolithicSparse disk and 1 being a twoGbMaxExtentSparse disk.