Preheat oven to 375 degrees F.
Cut squash in vertical pieces, about 1/2 inch thick. Place in a baking dish and coat with olive oil and 3/4 teaspoon salt.
Bake squash for 30-35 minutes, turning once, until squash is tender.
Meanwhile, massage kale for 5 minutes with hands, adding 1 tablespoon olive oil, 1/4 teaspoon salt, cumin, harissa, and 1/2 tablespoon lemon juice. Set aside.
Whisk all sauce ingredients together, and set aside.
When all components are ready, add to a large bowl. Pour sauce over the top, and gently toss and coat with your hands. Plate, and sprinkle with flaky salt.