Preheat your oven to 400°F and place the asparagus spears on a parchment-lined baking sheet, seasoning lightly with sea salt.
In a small bowl, combine the smoked paprika, garlic powder, onion powder, dried oregano, cayenne pepper, sea salt, and black pepper to create the blackening rub.
Pat the catfish fillets completely dry with a paper towel and coat both sides generously with the spice mixture, pressing it into the flesh.
Prepare the aioli by whisking together the Greek yogurt, avocado oil mayonnaise, lemon juice, and minced garlic in a small ramekin until smooth.
Heat the avocado oil in a large cast-iron skillet over medium-high heat until it begins to shimmer.
Carefully place the catfish in the hot skillet and sear for 3 to 4 minutes per side until a dark crust forms and the fish flakes easily with a fork.
While the fish cooks, roast the asparagus in the oven for 8 to 10 minutes and steam the cauliflower rice in a separate pan until tender.
Plate the blackened catfish over a bed of cauliflower rice with the roasted asparagus on the side, topped with a dollop of the lemon aioli.