after killing explorer.exe, tabs from launched apps appear over app

We have a kiosk machine running Win10Pro for which we kill explorer.exe on startup to avoid public access to the desktop via gesture swipes, etc.
Our kiosk runs multiple applications – sometimes it may even control and launch an additional app depending on process.
The problem we are having is that after explorer is killed and the main app is in the foreground, any additional app started will cause a visible small tab to be shown along the bottom of the screen. This kind of tab would normally be put into the taskbar but with no taskbar available, the tab becomes floating and visible.
Touching the main app will bring it back into the foreground, but if someone touches the tab they can expand it and see the associated terminal.
Does anyone know how to solve this; make sure apps are started in a hidden mode?