In about:config set browser.tabs.opentabfor.middleclick to true and instead of Ctrl + Click use Shift + Click on links to open them in new windows instead of tabs.

Also uncheck "Open new windows in a new tab instead" in Options in GUI or set browser.link.open_newwindow to 2 instead of 3 (it's the same thing) to make pop ups open in new windows instead of tabs.

There might be an extension to remap the Ctrl/Shift shortcut or abandon tabs altogether but I don't know of any.

Googling turns up results like https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plus/ but it's of course not compatible with Quantum.