I don't know what type they sell normally and I don't know the names they use around the mainland, but most of the sea cucumbers sold for aquariums ***should*** be sand shifters.
Some of the Holothuria spp. are very good. You'll need to make sure the species you're getting actually ingest the sand. Make sure you have a system safe for them. If they get in the pump or filter they can die and your tank will be a mess!! But it's very easy to make the tank safe. Just make sure they won't have access to the pump inlets and overflow. They are better than fishes to clean the sand, depending on the sand area you've got.
Hope others could get here to give you the names and share their experiences with the cucumbers...
Good luck!
Grandis.