Set the Instant Pot to SAUTE (normal heat). Add the oil, brown sugar, fish sauce, soy sauce, ginger, lime zest, lime juice and black pepper to the Instant Pot. Bring to a simmer, then turn off the cooker.
Place the fish into the cooker, with the flat side that had the skin up. Spoon some of the sauce over the fish. Cover the cooker and cook on LOW PRESSURE for 1 minute. Let the pressure release naturally for 5 minutes, then release the remaining pressure manually.
Switch the cooker back to SAUTE (normal heat) and cook your salmon and sauce for another 30 seconds - 1 minute or so, or until salmon is cooked to your liking.
Carefully lift the salmon from the cooker and place onto a rimmed serving platter, flipping them over so that the side that was down is now up. Continue cooking the sauce in your cooker until reduced and syrupy, about 3 minutes more.
Spoon reduced sauce over salmon and garnish with sliced green onion and cilantro leaves. Serve with fresh lime wedges for drizzling.
Preheat oven to 350F.Combine oil, brown sugar, fish sauce, soy sauce, ginger, lime zest, lime juice and pepper in an oven-proof baking dish just large enough to hold your salmon fillets flat. Place salmon fillets into dish with sauce, with the flat side that had the skin facing up.Bake in preheated oven for 20-25 minutes, or until salmon is cooked to your taste. Remove dish from oven, then remove salmon to a serving platter, flipping the salmon so the bottom side is now up. Place dish with sauce back into the oven under the broiler (about 6 inches from heat) to reduce and thicken the sauce slightly, about another 1-2 minutes or so. Spoon reduced sauce over salmon.Garnish with green onion and cilantro leaves and serve with lime wedges for drizzling.