There are some ways to do it in HTML, but one of the more simpler ways of going about it is by doing it through the social media tab in the general settings of the theme, or by using the external link in the menu manager.
Menu Manager is easier, Social Media tab looks better. Other than that, I'm actually pretty lost on how you could make a redirect function keep opening tabs in new windows. Some people can change it in their browser settings. But I believe if you try and go about doing it manually in the HTML, you could run into a bunch of problems and it's just not worth going through the trouble when there are easier and much less complicated alternatives.
If you'd like some assistance with the social media tab, check out these images (the HTML coding usually is already setup. All you have to do is change the href="yoururl" link
This can usually be found in your theme's general edit settings: Customization > Apperance > Themes > Edit (Pencil) > Social Icons