Step 1Place a rack in the lower area of the oven; heat the oven to 350 degrees. Set aside a buttered 6-cup shallow casserole.
Step 2Heat the oil in a large nonstick skillet over medium-high heat. When hot, add the zucchini, 1 teaspoon salt and pepper to taste. Cook, stirring occasionally, until the zucchini is almost tender but still a little crisp, about 4 minutes. Add the onion and garlic. Toss with the zucchini and cook over medium heat to warm through, 2 minutes. Remove the zucchini from the heat. Toss in the tomatoes, rice and 1/4 cup cheese. Transfer the mixture to the casserole and smooth the top.
Step 3Combine the remaining cheese and bread crumbs in a small bowl. Sprinkle the mixture evenly over the top of the zucchini mixture. Drizzle the top with olive oil.
Step 4Bake the casserole until the top is browned and bubbling on the edges, about 45 minutes. (This can be served immediately, but the dish improves if cooled and refrigerated overnight. To serve, reheat, uncovered, in a 350-degree oven until hot, about 30 to 40 minutes. Serve hot or warm.)