1. Soak plank in cool water for 10 minutes, weighing down with a heavy object to keep submerged.
2. Heat gas grill to medium or charcoal grill to medium coals.
3. In small bowl, stir together brown sugar, soy sauce, the clove of minced garlic and the sesame oil. Set aside 2 tablespoons sauce for serving.
4. Once plank is done soaking, place salmon fillet on plank, skin-side down, and brush with half of remaining sauce. Transfer plank to grill and cover. Grill 10 minutes; if plank chars too much, mist with water.
5. Uncover grill; baste salmon with remaining sauce. Cover grill and continue to cook 15 minutes or until fish registers 130 degrees F on an instant-read thermometer and flakes easily with a fork.
6. Meanwhile, heat oil in a large nonstick skillet over medium heat. Add the 2 sliced garlic cloves and cook 1 to 2 minutes. Add bok choy, salt and pepper and cook an additional 2 to 4 minutes, until tender and cooked through.To serve:
7. Slide a spatula between fillet and skin and transfer to a platter. Drizzle with the 2 tablespoons reserved sauce; serve with bok choy on the side.