Prepare the Roasted Sweet Potato and Chickpeas: Preheat the oven to 400°F (200°C). Line an extra-large (15 by 21-inch/38 by 53 cm) baking sheet (or two large baking sheets) with parchment paper.
Peel the sweet potatoes and chop them into small 1-inch (2.5 cm) cubes (you should have about 5½ cups). Place the drained chickpeas and sweet potato on the prepared baking sheet. Drizzle with the oil and toss until thoroughly coated. Drizzle on 1 tablespoon of the maple syrup and toss again to coat. Spread the sweet potatoes and chickpeas into a single layer on the pan. Sprinkle the pumpkin pie spice and salt all over the sweet potatoes and chickpeas.
Roast, uncovered, for 32 to 38 minutes (I roast for 36 minutes), until the sweet potatoes are fork-tender and golden brown on the bottom and the chickpeas are a bit shriveled. I don’t flip them or rotate the pan during baking.
Meanwhile, prepare the Marinated Kale Salad: Place the kale in a very large bowl. In a small bowl, whisk together the garlic, oil, maple syrup, salt, lemon juice, and tahini until smooth. Pour the dressing over the kale and massage it into the leaves with your hands until fully coated. Let the kale marinate in the dressing while the sweet potatoes and chickpeas roast.
When the chickpeas and sweet potatoes are finished roasting, remove the baking sheet from the oven and drizzle the remaining 1 tablespoon maple syrup over them. With a spoon, gently toss to coat. Taste and season with more pumpkin pie spice and salt, if desired (I always do!).
Portion the kale into bowls, top with the warm roasted sweet potatoes and chickpeas, and garnish with the roasted pepitas. Serve warm.