start activity com.android.settings/.applications.StorageUse

Worked for me on a MC3300 which is in the same Atlas product family as a TC75x. 

I would still be skeptical about giving end users this limited access as they could do some pretty damaging things from this menu.

There are MX based options that might be better suited to your needs. You could create a MX based profile in StageNow that clears the app cache that you're looking for. Then you could place that XML file on the device along with a cmd script file including the mxconfig SOTI script used to execute that XML. Then you could point a shortcut on your lockdown utility to the cmd script so end users could run it on demand. This way end users would never need to get into the settings app in order to clear an app cache as the process could be obfuscated into a simple button tap. 

Different device brands or firmware may have different names.  Thus, without a Zebra TC75X on hand to work on and check, I could only suggest that you try some possible default names such as 

  com.android.settings/.Settings$StorageSettingsActivity

  com.android.settings/.applications.StorageUse

On top of what Matt said in his post, I would like to add the following.

The UI and layout design of individual device Settings may heavily impact how secure your device or lockdown policy can be.  Not only are all features within a particular page configurable by any device end-user.  If there is any short-cut to access other Settings page(s) in the UI layout,  it can't be ruled out without thorough tests plus other protection policies applied, that any device end-user can change configurations on such Settings page(s), which might partially defeat the purpose of using a lockdown.

Thank you so much! I will try that out. I would definitely prefer a config file to giving users access. 

I am new to Stage Now but this is exactly what I needed. Thank you!