The affiliate hoplink URL is just this part:
https://www.e-junkie.com/ecom/gb.php?cl=XXXXX&c=ib&aff=YYYYY
The target="ejejcsingle" is not part of the link's URL. In the context of your complete linking code, that part just specifies that the link should open the seller's site in a new window/tab, so the affiliate's site will remain open in the original window/tab.
BTW, in case you haven't run across it yet, this is our help page for affiliates:
http://www.e-junkie.com/ej/help.for-affiliates.htm
...and this help page for sellers explains how to set up and manage an affiliate program using our system (which you may find useful as an affiliate as well):
http://www.e-junkie.com/ej/help.affiliates.htm