Preheat the oven to 400°F then line a baking sheet with parchment paper.In a large bowl, combine diced potatoes and chopped cauliflower. Pour high heat oil over top then sprinkle with spices and salt. Arrange vegetables on baking sheet, making sure to give the potatoes room. You may need to use two baking sheets. Bake in the oven for 20 minutes.The the same bowl, add chickpeas, jalapeño, and red onion. Stir until coated in any remaining oil and spices. Add more if needed. Set aside.Meanwhile, in a small bowl, combine yogurt, ginger, garlic and lemon juice + zest. Stir until mixed thoroughly then refrigerate.Remove sheet pan from oven. Stir cauliflower and potatoes then top with chickpeas and jalapeño. Return to oven for 15 more minutes, or until vegetables are tender.Serve warm with sliced red onion, cilantro and yogurt sauce, and enjoy!