Preheat the oven to 425°F. Peel the squash and cut it in two. Remove the seeds and stringy fibres, and dice the squash.
Arrange the squash pieces on a baking sheet lined with parchment paper. Drizzle with olive oil, add salt and pepper, and sprinkle with sumac or paprika. Roast for 25 minutes.
In a small saucepan, sauté ½ tbsp olive oil and the minced garlic over low to medium heat. Add the black beans, ground cumin, chili powder, salt and ¼ cup of water. Bring to a boil. Cover and reduce heat to low. Simmer for approximately 5 minutes or until the beans are well heated and soft (but not dry).
In a hot pan, heat the tortillas for a few minutes, or microwave them for 20 seconds. Cover with a clean cloth to prevent them from drying out.
Top the tortillas with roasted squash, black beans, avocado and feta. Serve with fresh cilantro, hot sauce and lime quarters.