Combine salt, pepper, garlic and onion powder in a bowl. Mix well.
Pour the oil in the bowl and mix with the spices.
Rub the oil mixture all over the salmon fillet. Let it stay for 15 minutes.
Heat-up the grill.
Meanwhile, place the salmon on the cedar plank.
Arrange the cedar plank with salmon on top of the grill. Cover the grill and continue to grill the salmon for 15 to 20 minutes, or until the salmon gets flaky.
Remove the salmon from the grill. Arrange in a serving plate.
Serve with lemon or calamansi.
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