Get a list of all files from the REST API as admin

I am developing an app that watches the use of files by users. I need to get a list of all files in the enterprise. I cannot see a way to query from a single user. That user can only see their own files even when they are a global admin. I have been using the endpoint,

https://{1}-my.sharepoint.com/personal/{0}/_api/files

1 being my site and 0 being the user. 

Thanks for any help.