All browsers that I know of have a feature to open a link in a new window. For most, it's as simple as holding down a modifier key (such as Ctrl) while you left-click the link, or middle-clicking the link.
For others, you might have to right-click and select the appropriate option from a context menu.
But whatever the option is, you should learn it for your browser and use it each time you want to do this. The web designer should not force his/her choices on us. I, for one, don't want everything to open in a new tab/window.
Also see the answers to these two questions for more about the community's general feelings on using
target="_blank" in links: