To prepare the dressing, whisk together the first seven ingredients until thick and homogenized.
Now, to create the salad:
- Heat oven to 400°. Combine squash, sweet potatoes, oil, and sage on large, rimmed baking sheet. Season generously with salt and pepper. Roast until tender, about 25 minutes.
- Transfer to a large bowl. Add farro, half the walnuts, half the pomegranate seeds, and all but ¼ cup vinaigrette; toss to combine.
- Toss kale with reserved ¼ cup vinaigrette and arrange on a large serving platter. Top with roasted squash mixture.
- Serve topped with remaining walnuts, pomegranate seeds, blue cheese, and sage leaves.