If you installed csi driver using YAML then run:
$ curl -fsSL https://raw.githubusercontent.com/kubevault/csi-driver/0.1.0/hack/deploy/install.sh \
| bash -s -- --uninstall [--namespace=NAMESPACE]
The above command will leave the csidriver crd objects as-is. If you wish to nuke all csidriver crd objects, also pass the --purge flag.
If you used HELM to install Vault CSI driver, then run following command
helm del --purge <name>