I'm afraid not. Once created, an alias cannot be moved to another account, or used as the login to create a new account, and if you delete it you can never reinstate it.
You can create new aliases in iCloud perfectly well, just as in MobileMe. Go to the Mail page at http://icloud.com , click on the cogwheel icon at bottom left and choose 'Preferences', then in the pane which opens click 'Accounts' in the toolbar. Click the plus sign below the list of addresses to create an alias.