If you want to delete signatures you set from SignatureSatori from all your users' accounts, you can do so in one click in Settings. This operation is free.
This option will apply a blank signature to them, effectively removing them.
If you want to remove a signature of an individual user, there are several ways how to go about it.
Delete the signature directly in user's Gmail settings
This is the safest and in most cases quickest option.
Switch to "No signature" in Gmail settings
This option is especially useful if the user doesn't want to delete the signature right away, they just need some time for it not to be displayed.
Set empty signature template
If user's Gmail setting is not reachable for you and you want to set the signature remotely, you can do that by setting a blank signature.