It is possible to resize a VMware .VMDK file without using the VMware tools.
The QEMU disk image utility comes with qemu-img a tool which allows you to convert virtual disk formats.
To resize a VMDK using qemu-img
# First convert the vmdk to raw format
# NB. Make sure you reference the actual disk image and not the .vmdk descriptor file
qemu-img convert linux-flat.vmdk linux.raw
# Extend the vmdk using dd.
# Here we are extending the disk to 16G using dd. The resulting file will be sparse
dd if=./linux.raw of=./linux-16G.raw BS=1M seek=16384 oflag=append ...
— Andrew