How to Make It
Heat oven to 400°F. Toss together squash, 2 tablespoons of the oil, 1 teaspoon of the salt, and ½ teaspoon of the pepper on a rimmed baking sheet.
Remove 1 clove from garlic head; peel, halve, and reserve clove for bread. Slice remaining garlic head in half crosswise. Combine chickpeas, ⅓ cup of the oil, ½ teaspoon of the salt, and remaining ½ teaspoon pepper in a 2-quart baking dish. Nestle halved garlic head, cut side down, into chickpeas.
Bake squash and chickpeas at same time until squash is tender and chickpeas are soft, 30 to 35 minutes. Scoop flesh from squash skins, and transfer to a large bowl. Add remaining 1 tablespoon oil and ½ teaspoon salt to squash; mash until smooth using a potato masher or fork.
Place bread on rimmed baking sheet. Spoon some of the oil from chickpea dish onto each bread slice. Bake at 400°F until edges are golden and toasted, 8 to 10 minutes. Rub toasted bread with reserved garlic clove. Top toasts evenly with mashed squash, pesto, and chickpeas. Squeeze roasted garlic cloves from skin, and divide among toasts.