To view all variable names you can use for fields within the system go to Forms - Fields Manager.
Ex: %user_field_1% is for inserting first name.
Now to add this this into a link you would go to your html editor or plain text editor and add the following string.
In Html Editor choose insert url or edit url button to get the URL button popup.
Once inside then your url would look something like this: http://yourdomain.com/%user_field_1%
This would result in http://yourdomain.com/firstname, of course first name woudl be the name of the person you imported within your emercury contacts list.