Ctrl+Click to open in new tab
For now, AFAIK, every action associated with a mouse click can be accessed using a touch or a long-touch. Combo using a key-press and a touch aren't well supported (if supported at all).

Long-Touch over a link, gives you a popup with:


Open in new Tap;
Open in incognito mode;
Copy link address;
Save link as.


For future reference, Google Chrome shortcuts link, from Google support page (the majority of the Linux links are available for Android... just waiting to have this page updated with the Android shortcuts list):

Google Chrome - Keyboard and mouse shortcuts