Soak cedar plank in water for 30 minutes, or up to 1 hour.
Preheat grill for medium-high heat.
Rub salmon fillets with olive oil. Lightly coat both sides with sea salt and pepper. Arrange salmon on the plank. Sprinkle half the lemon juice over salmon.
Cook salmon, covered, for about 20 minutes, until internal temperature reaches 145° F.