You can delete your account on the settings page of your user account. Please note, as soon as you delete your account, your cloud computer will be erased. You will forfeit the remainder of your balance in your cloud account. The account deletion has a grace period of 14 days for which you can change your mind, but after that point, all of your other data will be erased.
Click on the settings gear next to your name
Visit the Account section of settings
Click Deactivate Your Account and follow the instructions there