Use the Keyconfig extension to assign this code to your preferred keyboard shortcut:

BrowserOpenTab();

• http://kb.mozillazine.org/Keyconfig_extension
• http://dorando.emuverse.com/projects/mozilla/readme.html

Thank you, very much for this info! I manage to assign a "T" key for opening a new tab. I would like to ask too, is it possible to assign a double key pressing for closing and opening a tab. For example, to press two time "T" to open a new tab and to press "Q" two times to close the tab. I tried to do this with "keyconfig" but i couldn't.

Thanks!