Create Empty User as Admin, and force entering info on login
It's not possible to create a new user without email, username and password. 

The only workaround for this is to create placeholders. E.g. always enter username@example.com in the email field where username is the machine name of the user's full name.

As for creating the user without entering the required fields I think it's best to create a custom form. This form would only contain a textfield Full name.

On submit you dynamically generate the username, email and password (see drupal_clean_css_identifier to easily generate a machine name) and create the user object.

Here's a code example:

$full_name = $form_state['values']['full_name'];
$username = drupal_clean_css_identifier($full_name);
$email = $username . '@example.com';

//This will generate a random password, you could set your own here
$password = user_password(8);

//set up the user fields
$fields = array(
  'name' =&gt; $username,
  'mail' =&gt; $email,
  'pass' =&gt; $password,
  'status' =&gt; 1,
  'init' =&gt; 'email address',
  'roles' =&gt; array(
    DRUPAL_AUTHENTICATED_RID =&gt; 'authenticated user',
  ),
  // If you have custom field 'Full name' do this:
  'field_full_name' =&gt; array(
    LANGUAGE_NONE =&gt; array(
      0 =&gt; array(
        'value' =&gt; $full_name,
      ),
    ),
  ),
);

//the first parameter is left blank so a new user is created
$account = user_save('', $fields);