Place cedar planks in a large container and submerge completely in water. Soak for at least 2 hours, preferably 4-6 hours.

In a medium bowl, whisk together soy sauce, rice vinegar, grated ginger, minced garlic, honey, olive oil, and sesame oil to create the marinade.

Place salmon fillet skin-side down in a shallow dish. Pour two-thirds of the marinade over the salmon, reserving the remainder for basting. Cover and refrigerate for 30 minutes (no longer than 1 hour or the fish might become too salty).

Preheat grill to medium heat (around 350°F/175°C).

Remove soaked cedar planks from water and place on the preheated grill for 2-3 minutes until they begin to smoke and crackle slightly.

Carefully flip the planks over and place the marinated salmon on top, skin-side down. Close the grill lid.

Cook for 12-15 minutes until salmon is opaque and flakes easily with a fork. The internal temperature should reach 145°F (63°C). Baste occasionally with the reserved marinade.

During the last 5 minutes of cooking, sprinkle the sliced green onions over the salmon.

Carefully remove the cedar planks with the salmon from the grill and let rest for 5 minutes.

Garnish with lemon slices and fresh herbs before serving.