would fit the bill, as would New Zealand oysters. The latter are seasonal, and grow very large. They are served at my local Chinese restaurant with a ginger-and-shallots sauce. So large that only one or two will fit on the plate. Tender and succulent despite their size.
As for saltiness, this will be a function of preparation (washing and cleaning) rather than a species-specific attribute. Freshly shucked, lightly washed oysters are very salty.
Finally, my experience is that (as with prawns), the smaller the oyster variety, the better the taste. Hence I would neither eat the large NZ oysters raw, nor Sydney Rock oysters cooked.