If you're prepared to explore the Xania area the last time I walked along the waterfront of the inner harbour I noticed a few sailing craft plying for customers. Most were for day and ½ day "tours" but I did notice a couple that were advertising self-sail and/or crew wanted.
There's the Xania Yacht Club which would seem a reasonable place to get some leads. They have a Lounge Cafe at the extreme western end of Xania harbour but I've only seen junior activities there - youngsters being taught in small dinghies. I don't know exactly where are the main club premises but they're quite close to the café, apparently.
This site (not the club site) has contact details:http://www.sail-clubs.com/en/i/3779/Gre ... iling-Club
For contact details (Web link to the club site seems to be broken)
and this is their Facebook page: https://www.facebook.com/groups/114903085196673/about/