There are a lot of ways to do this but one easy way is to heat your oven to 350 degrees. Dust the pieces of salmon with the cajun spices (and salt if needed). Lay the fish skin-side-down on a baking sheet. Bake until the fish is just cooked through -- the rule of thumb is 10 minutes per inch of thickness. Some people like salmon on the rare side, in which case I'd check it after 7 or 8 minutes.