There is an option in the picking filter for this. Exit out of any tool you have open, then right-click in the canvas to bring up the pick filter and select the 3D submesh option:
This allows you to select a mesh on a cell - right-click to delete it:
but: This is not very intuitive. There should be the simply option 'delete the mesh' after click the solid or cell - not click after click, after click...
