Cook the brown rice according to package directions. ...or, for a fool-proof method, see my directions for Perfect Brown Rice.
While the rice is cooking, heat 2 teaspoons olive oil in a medium nonstick skillet on high heat. Add the onions and reduce heat to medium-high. Saute the onions gently until they are lightly browned. Add the garlic and continue to cook, until the onions are well browned. Watch the heat, reducing if necessary, so the garlic does not burn. Add to the rice once the rice is finished.
Heat the oven to 400F. Season the fish with salt and pepper. Schmere the fish lightly with the mayonnaise.
Heat a large skillet on high heat with the remaining 2 teaspoons olive oil (I used a cast iron skillete). Working in batches, add the zucchini slices to brown one side only and soften. Remove zucchini and let sit until cool enough to handle.
Wrap each piece of cod in zucchini, browned sides out from the fish. Dust the tops with Old Bay seasoning. Bake at 400F for 20 minutes, depending on the thickness of fish, until the cod flakes easily with a fork. Serve immediately over the Garlic Cilantro Rice. Yield: 4 servings.