Sorry for the short answer, but it really is simple: press shift when clicking links.
edit:
from comments, it seems indeed i misread the question. can you please check if this applies? it is meant for IE, but who knows. IE and Chrome share some of their configs.
a. Close Internet Explorer.
b. Click start->control Panel->Internet Options.
c. Click on the settings button under the section “Tab”.
d. Under “Open links from other programs in” select any one mentioned below to open other programs in new window.
• A new window - Opens links in new Internet Explorer windows.
• A new tab in the current window - Creates a new tab if an Internet Explorer window is opened; otherwise, opens a new Internet Explorer window
e. Click Ok twice.
f. Then check if the issue is resolved.
source: http://answers.microsoft.com/en-us/ie/forum/ie8-windows_other/link-open-new-window-instead-of-tab-how-can-i-set/3dc36402-e71d-4bb2-970b-bc58b00fa029