Preheat the oven to 425 degrees. Line a sheet pan with parchment paper. Toss squash with olive oil, salt, and pepper. On one corner of the sheet pan, add seeds with olive oil, salt, and pepper. Seeds will be roasted after 5 to 10 minutes and can be removed from pan. Roast squash for 20 to 25 minutes, until squash pieces are fork-tender.
Meanwhile, whisk together the dressing ingredients.
Gently toss squash with garbanzo beans, greens, and dressing. Place on a platter or in a salad bowl. Top with toasted squash seeds and serve.