1. Coat cold cooking grate of grill with cooking spray, and place on grill. Preheat grill to 400° (medium-high) heat.
2. Brush both sides of fish with olive oil; sprinkle with salt and pepper. Place fish on cooking grate, and grill, covered with grill lid, 4 minutes or until grill marks appear and fish no longer sticks to grate.
3. Using a metal spatula, carefully turn fish over, and grill, without grill lid, 2 minutes or just until fish flakes with a fork.
4. Serve with lemon wedges or sprinkle with zest, if desired.