you can automate user roles/ selective access through an import action. you can allow making the changes through a module on the Dashboard but to add these changes to the model you will need an import action.
You can certainly automate user access management from the dashboard. To delete users is something that can't be done but if you are thinking about removing the User's access from modules that surely can be part of the user access management.
To automate selective access removal, you can have a module dimensionalized by the list that you have selective access turned on and a fake user list. The module saved view should include user email as well as names/codes of the list items that the users have "No Access" to. You would then use this saved view to import into "Users".
For user deletion, if you are referring to deleting the user from the model, then I don't think there is a way to automate it.