Preheat oven to 475°.
Remove white papery skin from garlic head (do not peel or separate the cloves). Place in center of a large baking sheet or shallow roasting pan. Arrange zucchini and next 4 ingredients around garlic; spray vegetables with cooking spray. Bake at 475° for 15 minutes, and turn vegetables with a spatula. Bake an additional 15 minutes or until vegetables are lightly browned and tender.
Spoon vegetables and pan juices into a bowl. Separate garlic cloves, and squeeze to extract garlic pulp. Discard skins. Stir garlic pulp into vegetables. Stir in vinegar and next 4 ingredients; toss gently. Let vegetable mixture stand 10 minutes.
Split French bread in half lengthwise, cutting to, but not through, other side using a serrated knife. Spoon vegetables onto bread; sprinkle with cheese. Bake at 475° for 3 to 4 minutes or until cheese melts. Cut into 4 equal pieces. Serve immediately.