Preheat oven to 450°F. Arrange cod fillets in center of large baking sheet. Toss together red pepper, red onion, zucchini and tomatoes. Drizzle with oil and sprinkle with salt and pepper; toss to coat well. Scatter evenly around fish.
Bake for 10 minutes; turn fish over and toss vegetables. Bake for about 10 minutes or until fish is golden and cooked through, and vegetables are tender.
Chimichurri Sauce: Meanwhile, stir together vinegar, salt, garlic and shallot. Let stand for 5 minutes. Stir in cilantro, parsley, oregano, chives and hot pepper flakes. Whisk in olive oil.
Arrange vegetables on plates; top with cod fillets. Drizzle with sauce (leftover sauce can be tightly covered and refrigerated for up to 3 days).
Transform this entrée into a sandwich by wrapping in a tortilla or pita bread lined with baby spinach.