According to Kicad/eeschema/General Commands, Control-Shift-Click will delete the selection. But unfortunately on the Mac, Control-Click is a contactual click, the same as right clicking, so all Control-Shift-Click does is open the contextual menu.
The same issue applies for dragging a block.
Is there an alternative set of modifiers that can be used fro deleting or dragging a block that avoid the control key?