Shortcut to toggle the Left viewport panel:
viewport.hide ?+ tag LayoutMODOXXCentrePanelLeftTabsVPTag left LayoutMODOXXCentrePanelLeftVPKey
Shortcut to toggle the Right viewport panel:
viewport.hide ?+ tag LayoutMODOXXCentrePanelTabsVPTag right LayoutMODOXXCentrePanelVPKey
N.B. These commands are one line.
Set the shortcut using the Input Editor under the System menu.