In a small mixing bowl, combine the Cajun seasoning, smoked paprika, garlic powder and onion power.
If needed, remove the skin from the salmon. Sprinkle onto the salmon filets, generously, and press into the salmon.
In a large skillet, melt the butter and then saute the salmon, seasoning side down for 3 to 4 minutes per side, or until cooked through. Once cooked, set aside and assemble sandwiches.
Slice and toast the ciabatta rolls, then add Ranch dressing, the blackened salmon filet, and sliced cucumber to each sandwich.
Serve Blackened Salmon Sandwich with side salad.