Okay, so the short answer is there is no "Free Up Space" command available (yet) in Desktop Connector that allows you to clean up the local workspace without removing the files from the cloud (Autodesk Drive). The reason I say yet is because it is currently in development.
Keep in mind that Desktop Connector will always show you the files that are in the cloud which can make it seem like all of your files are on your local machine when in fact files are only brought down on demand. (Open, download, etc) You can check the local state by adding the "local state" column in windows explorer.
In the meantime, there is a workaround that might be useful for you. If you put Desktop Connector in offline mode you can then use "Delete local" on the file(s) in your local workspace, upon returning online you will see that the local state for those items will show they are no longer cached.
- Right click on the Desktop Connector icon in your windows system tray
- Choose "Work Offline"
- In windows explorer navigate to the local workspace "C:\Users\username\ADrive
- You will then see the files that are on the local machine**, right click on the file and choose "delete local". You will be shown a dialog informing you that "Objects deleted while in offline mode are only deleted locally".
- Return Desktop Connector back online (step 1 and 2)
**Note: Only the files you have used in the last 15 days will be shown in offline mode and therefor you can only use the delete local command on those files.
Hopefully this can get you what you need while we continue to work on adding the "Free up space" (clear cache) command.

Craig S. Godfrey
Sr. Product Manager