Hi,
I would like to be able to hide the users email address in the user profiles and instead have a link to send them a mail. On clicking this link it would send the user a mail after which the user can chose to reply and then have a conversation with the sender. 

Could someone kindly help me on how i can do this in k2 or any other extenstion or plugin for k2.

Thanks
Prashanth

Take a look at users.php
search for email
I think you can change the code there
It would be best to do this in a k2 override so as not to change the core