Can anyone tell me how to change my username?
You can not change the username i.e. https://community.emc.com/people/dwilk1973 but you can certainly change your display name from Edit profile & privacy section.
To do that: Go to: https://community.emc.com/people/dwilk1973
Click: Edit profile & privacy
Check My Name I have done the same:
My userid is different and display name is different.
That stinks. Is there a way to just delete my profile?
Nope. But you can defintely create a new one with new email address!