Pat all sides of the cod dry with a paper towel, then season generously with salt and black pepper on both sides. If using frozen, make sure the fillet is fully thawed and pat dry very well or it will steam and not crispen up.
Dust with the flour, then shake off any excess.
Add the olive oil to a cast iron or stainless steel skillet over medium high heat. Warm up for 1 minute, or until glistening and hot.
Lay the fillets in away from you to prevent oil splattering. Cook untouched for 3-4 minutes on each side, until opaque and easy flakes. Use a spatula to flip.
In a smaller saucepan, or removing the fish to use that same skillet, add the lemon zest and lemon juice. Reduce heat to medium. Stir until warmed, about 1, then stir in the butter until a creamy sauce. Remove from heat immediately.
Serve the pan fried cod over the coconut rice and drizzle with the citrusy lemon butter sauce. Garnish with fresh cilantro, pickled onions, and cracked black pepper to enjoy immediately.