Heat olive oil in a large sauté pan (large enough to fit the fish fillet) over medium heat. 

Place the fish skin-side down into the heated oil and cook for 3 minutes. Carefully slide a spatula between the skin and the fish. Lift the fish out of the pan onto a clean plate. Remove the skin from the pan and the fish and discard, keeping as much fish oil and olive oil in the pan as possible. 

Return the heat to medium if the pan has cooled. Add the curry paste and sea salt. Stir, continuously, for 45 seconds to 1 minute until fragrant.

Add the coconut milk and whisk until completely mixed. 

Bring to a boil and immediately add the fish, former skin side up.

Cook for 8 to 10 minutes (depending on thickness), spooning sauce over the fish periodically. If your fish will hold together well enough, gently slide your spatula underneath and turn it skin side down. Continue to cook for a couple of minutes more until desired doneness.

Once fish is cooked to your preference, remove it from pan to your desired serving platter.

Return sauce to medium heat and reduce for 3-5 minutes, stirring frequently until it reduces and thickens.

Remove the sauce from heat, stir in fish sauce and lime juice.

Serve salmon or steelhead with Massaman curry sauce spooned over the top. Garnish with sliced green onions, cilantro and basil and lime wedges on the side.