1. Thaw phyllo dough overnight in refrigerator, or for two hours on counter. Preheat oven to 350 degrees.
2. Boil sweet potatoes until tender. Drain well and mash, adding cumin, salt, and pepper.
3. In a separate pan, saute fresh greens with garlic in olive oil until tender. Press the greens against a strainer to remove all the liquid. Chop the cooked greens. Fold the greens into mashed sweet potatoes.
4. Layer 2 sheets of phyllo dough; spray each with olive oil spray. Cut into two long strips. Place 1 - 2 tablespoons of filling 1" from edge of phyllo dough. Fold corner over into a triangle. Spray outside with olive oil.
5. Bake triangles on cookie sheet 20 - 25 minutes or until golden brown and crispy. Repeat with remaining phyllo sheets. Cut in half to serve. (The filling will be VERY hot, so let cool a few minutes).