Preheat the oven to 375 degrees F.
Prick the sweet potatoes all over with a fork. Place them on a sheet pan and roast for 45-55 minutes until they are just tender. You should be able to easily piece them with a knife.
Let the sweet potatoes cool for 5-10 minutes before halving them lengthwise and fluffing their flesh with a fork.
Give the sweet potatoes a slight head start baking in the oven. Then prep the chickpeas. In a small bowl, toss the chickpeas with 1 tablespoon olive oil, 1 teaspoon cumin, 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper.
Spread the chickpeas in a single layer across a sheet pan. Bake for 30-35 minutes until they are crisp and browned, gently shaking the pan about halfway through roasting.
Toward the end of the roasting time for the chickpeas, warm 1 teaspoon olive oil in a small skillet over medium heat. Sauté the spinach until the leaves start to wilt, about 2 minutes. Add the minced garlic, 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper, and continue cooking until fragrant, about 1 minute.
Spoon the chickpeas and spinach into the sweet potato halves. Drizzle with tahini and sprinkle with flaky sea salt and red pepper flakes before serving.