In Rules Fetch Contact Entity from Tag Creation
You'll need the module CiviCRM Entity installed. https://drupal.org/project/civicrm_entity
You will also need the Webform Rules module https://drupal.org/project/webform_rules

What you could do is add a checkbox for each contact that can be deleted to the webform, could just be a regular Webform component. 

Then respond to the submission of that webform with a Rule. 

In the submission data, there will be a value for the checkbox you add. If it is checked, then load the contact by cid, it will also be there in the submission data. 

With CiviCRM Entity, CiviCRM entities like contact, become proper Drupal entity types, in this case civicrm_contact is the entity type. You can then use the regular "Delete an entity" Rules action. 

Before you delete the contact, you will have to load it first. There is a Rules action, "Fetch entity by id", use this, and pass it the contact id you get from the webform submission data.