Mix together the Cajun seasoning and oregano in a shallow bowl.
Brush the salmon on both sides with a little oil and coat with the spice mix, making sure the fish is completely covered. Set aside.
Meanwhile, make the salsa by mixing together all the ingredients in a bowl. Season to taste and set aside.
Cook the salmon in a preheated, dry frying pan for 4 minutes on each side.
Slice the salmon and serve with the salsa, with lime wedges to garnish.