How to grant or allow a particular SQL Server Login/User to always view a Column Level Encrypted data?
There is no out of the box way to automatically open a key for a particular user. You could create a logon trigger that opens the symmetric key. Something like this:

CREATE TRIGGER open_sec_key
ON ALL SERVER
FOR LOGON  
AS  
BEGIN  
  IF ORIGINAL_LOGIN() = '&lt;user&gt;'
   OPEN SYMMETRIC KEY [key_name] DECRYPTION BY CERTIFICATE [cert_name];
END;


Logon Triggers.