KNO3 is used for preserving fish here in Sweden. I don't have any at the moment, but I think it tastes "salter" than table salt and a bit "cold" like somone said.
That's probably the reaction (KNO3 + H2O = K+ (aq) + NO3-(aq) ) being endothermic. I could list what pyro salts I've tasted taste like, but firstly I do not want to encourage other people (barium, perchlorate and other poisons) and secondly it's a bit off topic