You could use workflow to make a new user and grant it rights to the document in question.  Those rights could specify that they can't print or download it.  Workflow can also generate a URL to that document and include it in an email.  Finally, it could delete the account after a specified amount of time.  Note that with this approach the user will require a license in order to see the document, so there may be more work to do in terms of allocating a user license, or having a pool of users set aside for this purpose.

There are other solutions possible...  you could export the document to a location and have your own web application enforce authentication.  It depends on how polished you want it to be and what kind of resources you have available.