Preheat oven to 425°.
Remove white papery skin from garlic head (do not peel or separate the cloves); wrap in foil. Line a baking sheet with foil; coat foil with cooking spray. Arrange tomato wedges in a single layer on foil. Bake garlic and tomatoes at 425° for 40 minutes, turning tomatoes after 20 minutes. Remove tomatoes from oven; bake garlic an additional 5 minutes. Remove garlic from oven; cool 10 minutes. Separate cloves; squeeze to extract garlic pulp. Discard skins. Mash garlic pulp and goat cheese with a fork until blended.
Spread 2 teaspoons goat cheese mixture over each bread slice. Top each with 1 tomato wedge.