Dynamically change email recipient in webform based on dropdown list
I assume the view you are using creates an option list of key|value pairs of the form nid|Restaurant name. For this answer, I will call your select element restaurant.


Install and activate the Webform node value module. This is a new module, and you will have to apply this patch. (If you are not familiar with patches have a look at Applying Patches.)
Edit your webform, and under Form components create a "Hidden" webform element called send_to_email.
Under E-mails add Component value: send_to_email as the to address.
Under Form settings go to the bottom and open the Set Value From A Node group.


The Path To Node is From webform field.
Since the key returned is nid, set the Path Alias Prefix to node/ so the nodes can be found using node/nid as the path.
The Webform Source Field is restaurant (your select element).
If the field containing the email address of the restaurant is $node->field_email, set the Node Source Field to field_email.
The Webform Target Field is send_to_email.