Pat the catfish fillets dry with a paper towel to ensure the crust adheres properly.
Whisk the egg in a shallow bowl and in a separate shallow dish, combine the cornmeal, smoked paprika, garlic powder, sea salt, and black pepper.
Dip each fillet into the egg wash, then dredge in the cornmeal mixture until fully and evenly coated on all sides.
Heat the avocado oil in a large non-stick skillet over medium-high heat until shimmering.
Carefully place the catfish in the pan and sear for 4 to 5 minutes per side until the crust is golden and the fish flakes easily with a fork.
While the fish cooks, steam the green beans in a steamer basket over boiling water for 5 to 6 minutes until tender-crisp.
In a small bowl, stir together the Greek yogurt, finely chopped dill pickles, capers, and lemon juice to create the tartar sauce.
Plate the catfish immediately with a generous dollop of the yogurt tartar sauce and the steamed green beans on the side.