Preheat oven to 400 degrees F. Toss the squash together with the olive oil, salt and pepper. Spread out on a baking sheet and roast until tender when pierced with a fork, about 30 minutes. Allow to cool slightly.
Arrange the arugula on a large platter and top with the squash. Add the feta and avocado.
For the dressing
Blend together all ingredients until smooth. I used my hand immersion blender since this is a small job. A mini food processor would work nicely as well. Drizzle dressing over top of the salad and serve.
Notes
Ensure your tahini is nut-free if you are allergic (some contain peanut oil).