Finding olives with lower sodium content at stores is nice, but they still contain quite a bit of salt. Tom tends to end up eating more than he probably should, thinking each fruit is small ... one more is OK ... another is still OK ... maybe one more ...
Soaking olives in water with a tiny amount of salt can take care of desalination.
According to my kitchen tests, when olives are soaked in cold water (50F/10C), their sodium content is reduced by approximately 30% after 1 hour, 40-50% after 2 hours, and 60+% after 3 hours.