Step 1Combine one-fourth cup of the olive oil with the garlic, lemon juice, coriander, salt and pepper in a large bowl.
Step 2Add the cod. Cover and marinate 1 hour.
Step 3Cook the filets on an oiled grill until the fish flakes easily with a fork, about 3 to 4 minutes per side.
Step 4While the fish is grilling, place the chiffonade of sorrel, the tomatoes and the dill in a bowl. Drizzle with the remaining 2 teaspoons of olive oil, sprinkle with salt and pepper to taste and toss.
Step 5Remove the fish from the grill. Spoon the sorrel mixture on top of the hot filets, allowing the greens to wilt slightly, and serve.