AFAIK, VO+Command+Return can be used to select multiple things, not to click. For example, in the file viewer (Finder.app, similar to Nautilus/explorer.exe), it is similar to pressing Control (win/linux) and the left mouse button when the cursor is over a file to add it to the selection.

Edit: To open a page in a new tab in a Firefox with stock VoiceOver, I need to press VO+Shift+M to open context menu (aka right-click menu), and then select an option from the list (by greping, using arrows etc.).

I know several non-technical people who find the distinction between window and tab difficult to manage for instance. As well as people who have had Android mobiles for years and still don't understand those three little buttons at the bottom of the screen: back, home, 'task' list.