This question was closed as subjective and argumentative. It is, as Aaronut said, at least a list of X and should be CW, but I think the list would be small, and can see that it is useful. I don't want to vote to reopen without a discussion about it though.
To me it seems like a great question. The OP wants to know how to go about testing the differences in tastes between various salts, how the different salts have different flavour effects on the thing they are salting. Now I don't believe that you can do this by either
- Eating a little of the raw salt
- Cooking a recipe with different salts and tasting the difference
To just see the effect of the salt I think you need to have a simple, preferably single food. My suggestion was a slice of tomato, but the other suggestions of bread and butter or a little salmon would probably be good too.
This would showcase the difference between no salt and different types of salt which is what the OP is asking.
Seems reasonable to me.
Why am I wrong?