1. Prepare grill to medium-high heat.
2. To prepare relish, coat bell pepper pieces with cooking spray. Place pepper pieces on a grill rack; grill 3 minutes on each side or until lightly charred. Remove from grill; cool slightly. Coarsely chop bell pepper pieces. Combine chopped bell peppers, parsley, and next 6 ingredients (through garlic); set aside.
3. To prepare fish, brush 1 tablespoon oil evenly over fish. Sprinkle fish evenly with thyme, 3/4 teaspoon salt, and 1/2 teaspoon black pepper. Place fish on grill rack; grill 4 minutes on each side or until fish flakes easily when tested with a fork or until desired degree of doneness. Serve with relish.
Wine note: This dish begs for a good sauvignon blanc. Bell peppers, herbs, and capers all have bold flavors ranging from fresh green to herbal to briny. A good sauvignon will mirror all the green flavors here and provide a crisp counterpoint to the subtle flavor of the fish. Try the Kunde Sauvignon Blanc 2007 from the Sonoma Valley (about $16). —Karen MacNeil