1 - If you see a portrait icon on the top left of your Wakatoon menu, it'll mean you're logged in to your Wakatoon account. Then click on it. Then you'll be able to click on "remove my account".
2 - If you're not logged onto your Wakatoon account, log in, and go to 1.

3 - Otherwise, write to support@wakatoon.com and request the removal of your data, and we will remove them in a few days.