To create base, slice small part of one side of squash. Trim ends from squash, cut in half lengthwise and scoop out sides. Place cut-side down and cut squash into 1/4-inch thick slices. Place on sheet tray and toss with olive or pecan oil and salt. Roast until squash and peels are tender, 30-40 minutes.
While squash is roasting, heat small skillet over medium heat. Add pecans and toast, shaking pan, until nuts are fragrant. Transfer 1/3 cup of pecans to bowl and reserve remaining pecans for topping. Add oil, vinegar, maple syrup and salt while nuts are still warm. Stir vigorously and set aside.
In large bowl, combine spinach, farro, shallot, half the squash and half the dressing. Toss to combine then lay remaining squash on top of salad. Drizzle with remaining dressing and sprinkle with goat cheese and remaining toasted pecans before serving.
Notes
Note: Acorn squash skin is edible but needs roasting long enough to make it tender. If unsure, use delicata squash or skinless butternut squash.