How to create a drupal 'contact me' link where the user is a contact reference field of Contact B in a civi relationship
There may be a reason you want this as a 'drupal contact me' link but if you have the contact ID for the person you are wanting to be contactable in your View, then you should be able to provide a link to a webform with that cid1=x and therefore load that persons details in to the webform and use that as your 'contact me' option.

But to try and answer the other question, I would expect you to be able to add a 'drupal user' relationship to your existing relationships in the view, and set it to use the existing relationship that relates to the contact person