Simple Paypal question

I want to do a simple adjustment on the paypal module. At checkout when you are taken to paypal for payment, I want the paypal page to open in a new window. Where do I go to add a target=_blank tag?

That is not wise. Doing that leaves the customer's order open and incomplete, leaving them with confusion thinking they haven't placed an order yet.
The whole idea is to have them go TO PayPal, and then when they come back, they're shown their finalized order, thus completing the shopping process.

Thanks for the information. I am not using ssl, so how what do I do to keep the average buyer interested in my site. The media is telling everyone to look for the 'https' when buying online. You won't see that until you are transferred to paypal for payment, by then someone may think that it is not secure before they confirm to pay. The reason I was asking the question at first is because I wanted to "wrap" my zencart site into my Joomla site, but since I am not using SSL, the payment page would come up wrapped inside an unsecured page. I thought if I made the payment page open in a new window that would make the experience a little more appealing.

Rather than try to trick your customer (they don't like that), why not just get an SSL certificate for your site ?
You can get one for under $50, and that would protect your customers' address information ... which can be viewed as being just as critical as their CC information.
It'll be a LOT simpler to do that than to try and fudge the system to trick the customer ...