In a small bowl, combine the smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne pepper, sea salt, and black pepper to create the blackening seasoning.
Pat the catfish fillets completely dry with paper towels and coat both sides generously with the prepared spice mixture.
Heat the avocado oil in a cast-iron skillet over medium-high heat until it begins to shimmer.
Place the catfish in the hot skillet and sear for 3-4 minutes per side until a dark crust forms and the fish flakes easily with a fork.
While the fish is cooking, steam the green beans for 5-6 minutes until they are bright green and crisp-tender.
Prepare the remoulade by whisking together the Greek yogurt, Dijon mustard, hot sauce, and lemon juice in a small ramekin.
Plate the blackened catfish alongside the steamed green beans and serve with a dollop of the creamy remoulade.