Soak plank in enough water to cover for at least 1 hour before grilling; drain.
For tomato pesto, in a food processor or blender combine the dried tomatoes, pepperoncini, garlic, shallot, and 1/4 teaspoon salt. Cover and process until almost smooth, adding 2 to 3 tablespoons reserved oil, if necessary. Stir in 2 tablespoons basil and set aside.
For a charcoal grill, arrange medium-hot coals around edge of grill. Place the plank on the grill rack directly over the coals for 5 minutes or until plank smokes and crackles. Set aside 1/2 cup of the tomato pesto. Season salmon with remaining 1/4 teaspoon salt and the pepper. Spread remaining tomato pesto over salmon. Place salmon, skin side down, on plank. Place plank in center of grill rack. Cover and grill for 10 to 12 minutes or until fish begins to flake easily when tested with a fork. (For gas grill, preheat grill. Reduce heat to medium. Adjust heat for indirect cooking. Place plank on grill rack over heat for 5 minutes or until smoking and crackling. Place salmon on plank. Place plank over unlit side of grill and grill as above.)
Stir cherry tomatoes into reserved pesto. Serve salmon with pesto and sprinkle with additional basil, if desired.