Your email address is placed there by PayPal because you're using a Premier account.
You could have it replaced with a Business Name if you upgraded to a Business Account instead.
But you can't just remove it.
If you wish to style page according to your own preferences, you can login to your PayPal account, click on Profile, and then on Page Styles, and build a custom style there. Then take the name of that style and enter it into your Zen Cart Express Checkout module settings so that customers will see that newly-styled page when they visit PayPal.
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Furthermore, any advice you see here about PCI matters is merely an opinion, and should not be relied upon as "official". Official PCI information should be obtained from the PCI Security Council directly or from one of their authorized Assessors.