In a small bowl, whisk together 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 a paper towel and coat both sides evenly with the prepared spice mixture.
Prepare the remoulade by combining the Greek yogurt, Dijon mustard, lemon juice, and capers in a small dish; stir until well combined and set aside.
Heat the olive oil in a skillet over medium heat, add the green beans, and sauté for 5-7 minutes until they are bright green and crisp-tender.
In a separate heavy-bottomed skillet or cast iron pan, heat the avocado oil over medium-high heat until it begins to shimmer.
Place the seasoned catfish in the hot pan and sear for 3-4 minutes per side until a dark crust forms and the fish flakes easily with a fork.
Serve the blackened catfish immediately, topped with a generous dollop of zesty remoulade and the sautéed green beans on the side.