Preheat over to 425F. Slice delicata squash in half, lengthwise. Use a spoon to scoop out and discard the seeds. Slice the halves again lengthwise and continue to do so until you have thin squash slices similar to potato wedges.
In a mixing bowl, combine squash slices, olive oil, agave, red onion, thyme, chile powder, garlic powder, and salt. Toss well to coat then pour onto a baking sheet. Roast for about 15 minutes then toss and roast again for another 15-17 minutes.
While the squash mixture is roasting, combine all ingredients in a mixing bow for Feta-Peppercorn dressing. Whisk until the mixture is smooth like a creamy salad dressing. Set aside when done.
Add parchment paper to an air-fryer or to a rimmed baking sheet and spread out walnuts. Toss with olive oil, nutritional yeast, and breadcrumbs. If using air fryer, cook for 7 minutes at 400F. If using the oven, wait until the squash mixture has about 7 minutes left then add the walnuts to the oven. Toss halfway through to ensure they are golden brown.
Pour washed kale and half of the salad dressing into a large mixing bowl. Use your hands to massage the dressing into the kale until the greens are soft. Add the squash mixture to the serving bowl once they've cooled alongside the roasted walnuts and remaining dressing. For serving, garnish salad with additional crumbled feta cheese.