Uninstall app for all profiles On my tablet I have created restricted profiles for the kids. These restricted profiles have "app protection" enabled to prevent accidental uninstallation of apps.

Uninstalling an app that is enabled in the restricted profiles is quite cumbersome: I uninstall it in the owner profile. After this, it is still present in the restricted profiles. So I disable the app protection for all restricted profiles, then login into all the restricted profiles one after another, uninstall the app there, and finally I return to the owner profile and re-enable the app protection of the restricted profiles.

Is there a way to uninstall the app for all profiles in a single step?

I do not have root access on the device.
Note: Depending on your device and ROM, you may have to disable app protection before trying this (thanks to Andrew T.'s comment).

Try this: 


Open the App Info screen for that app. You can access this from Settings > Apps. Note: Depending on your launcher, you may also be able to access it from your home screen. In the stock android Launcher and Cyanogenmod's Trebuchet (along with apps building on one or the other), you can press and hold the app icon in the drawer, as if you were going to place it on your home screen, but at the top,  there are two options: uninstall and app info. You would want to drop the app on app info.
There should be a button in the top right corner of the App Info screen, "More." After pressing that button, an option should be revealed to "Uninstall for all users." See below for picture.




You can read more about the UserManager at the UserManager API page.