Are epidermal bladder cells not the cells you are looking for? They participate in sodium sequestration and water storage. I've also found this: http://www.agritech.tnau.ac.in/agriculture/agri_salinity_tolerance.html.
A scheme of the salt gland is in a book 'A Text Book Of botany: Plant Anatomy and Economic Botany, Volume 3. By Pandey S N, S. N. Pandey, Ajanta Chadha (Google Books). Best regards, Renata