How do I create a generic link including the username in it?

Hi! In the NETWORK Theme when you get requested to be a friend you get an email and when you click you have to log in, and then it takes you to the home instead of the Requests page: So I will solve this by putting a link on the home page that says Friendship Requests with the current usernames ID in the link. The problem is that I don´t know how to do that link I don´t know how to tell the system to take the "current" user to his page I´m missing a way of inserting in the link!

Can you help me please?