Fopnu already supports user links.
To get your own user link, find yourself in a chat room and right-click and Copy Link.
OR find yourself in a search, right-click and Browse yourself, then the button at the top with your user name in it can be right-clicked, where you can Copy Link.
OR add yourself to your own contact list. Then you can right-click yourself at any time and select Copy Link.
TO OPEN A USER LINK: right-click one of the main view buttons (eg. Network) and then select Open Links. A user link can be pasted right in there. OR if the link is in an email or web-page, you can simply click it and it should open in Fopnu. For example, fopnu:user:m5ny4nryqqbfaewh4bidqxvtw3kk3rsyi2ag6arae6ohospk4rqq/papa%20smurf%20is%20real