In a small bowl, whisk together the smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne pepper, sea salt, and black pepper.
Pat the catfish fillets completely dry with a paper towel to ensure a crispy crust, then coat both sides of the fish generously with the spice blend.
Heat the avocado oil in a large cast-iron skillet over medium-high heat until the oil is shimmering and just starting to smoke.
Carefully place the fillets in the hot skillet and sear for 3 to 4 minutes per side, without moving them, until a dark crust forms and the fish flakes easily with a fork.
While the fish is cooking, steam the green beans for 3 minutes, then drain and toss them in a separate pan with the ghee and a pinch of salt until tender-crisp.
Remove the catfish from the heat and let it rest for 1 minute before serving alongside the buttery green beans.