Place the flour in a shallow dish and add salt and pepper to season it, mix. Coat both sides of the sea bass fillets with the flour.
Heat a cast iron or oven-safe skillet over medium-high heat. Add canola oil and swirl to coat the bottom. When the oil hot and begins to shimmer, place the coated fish in the hot skillet and cook until the bottom browns. Turn the fish over and cook for 1 minute.
Place the skillet in the oven and bake for about 8 minutes, and then take out of the oven to test for doneness. Place a fork into the thickest part of the fish at a 45 degree angle and lift gently. The fish should be opaque, not translucent and should easily flake when done. If it needs more time, return to the oven for 2 minutes. It should be cooked through and brown on both sides.
While fish is cooking, pound garlic cloves with the flat side of chef's knife, peel and trim the end, then chop into a fine mince. Place half of the minced garlic in a small bowl, reserving the rest for the spinach. Add 2 tablespoons olive oil, capers with juice, lemon juice, salt, pepper, oregano, and parsley. Whisk together to incorporate and set aside.
For the spinach, heat a skillet over medium-high heat. Once hot, add 1 tablespoon olive oil, reduce heat to medium low and add remaining minced garlic, salt, pepper, and oregano to pan. Cook until garlic is aromatic. Add blanched spinach, stir and cook until the spinach is hot.
Once the fish is cooked, the sauce is made and the spinach is sauteed, plate the dish. Place spinach on the plate, taking care that no moisture pools from the saute. Top with sea bass and finish with lemon sauce.