Press the ctrl key when left clicking on the link for a new background tab (middle clicking creates a new background tab also)
ctrl shift when clicking on the link for a new foreground tab (shift middle click also works).
For extensions to try, here's an Opera extension, Open New Tab.
https://addons.opera.com/en/extensions/details/open-new-tab-2/?display=en
If you hold your click a bit longer, you get the new tab.
And here's a chrome extension, Click to Tab.
https://chrome.google.com/webstore/detail/click-to-tab/ebicmkkcnhdiglneianohfjapmanjoek
Remember, to download a Chrome extension easily, you need the Opera extension, called Download Chrome Extension, https://addons.opera.com/en/extensions/details/download-chrome-extension-9/?display=en
or Extension Source Viewer, https://addons.opera.com/en/extensions/details/extension-source-viewer/