Preheat oven to 375°F. Stir together drained and rinsed chickpeas, 1 Tbsp. olive oil, 1 Tbsp. Aleppo pepper, 1 tsp. garlic powder, and 1/2 tsp. kosher salt in a bowl. Transfer to a rimmed baking sheet. Bake 15 minutes. Using the same bowl, stir together coarsely chopped walnuts, chopped kale, 1 Tbsp. kosher salt. Stir into baked chickpeas. Bake until kale is crispy, 18 to 20 minutes. Stir in lemon zest.