Pat salmon fillets completely dry with paper towels. Rub each fillet with olive oil, then season generously with Cajun seasoning, salt, and pepper on both sides. If time allows, let seasoned salmon sit at room temperature for 10 minutes for more even cooking.

For pan-searing: Heat skillet over medium-high heat until properly hot. Place salmon skin-side down and cook for 4-5 minutes without moving. Flip carefully and cook another 3-4 minutes until salmon flakes easily and reaches 145°F internally. For baking: Preheat oven to 400°F (200°C), place seasoned salmon on parchment-lined baking sheet, and bake for 12-15 minutes until cooked through.

While salmon cooks, make avocado lime crema. In blender or food processor, combine avocado flesh, sour cream, lime juice, cayenne pepper, salt, and cilantro. Blend until completely smooth, about 30 seconds. Add water one tablespoon at a time until it reaches a ranch dressing consistency.

Once salmon is cooked through (internal temperature should reach 145°F and flesh should appear opaque), let rest for 2-3 minutes. Serve immediately with generous dollop of avocado lime crema on top.