It depends on what kind you are talking about--hot smoked or cold smoked--
or just cured.
Hot smoked is soaked in a brine basically to kill any surface parasites. It is rinsed and then smoked hot.
Cold smoked is also brined/cured but smoked over VERY low heat--100*.
And then there is gravlax which is soaked in various things for flavor and is not smoked at all but takes on the sense of lox. The version of this I make has vinegar/acid in the marinade and it basically "cooks" the salmon if left long enough.