Bring a large pot of water to a boil. Add sweet potatoes, and cook for about 5 minutes, or until tender. Drain, and set aside.
While the sweet potatoes are boiling, heat 1 tablespoon oil in a large skillet over medium-high heat. Saute the onion and green pepper with until tender. Season with cumin, salt, and pepper.
In a large bowl, toss together the sweet potatoes, onion mixture, and turkey. Heat remaining oil in a large skillet over medium heat. Place the sweet potato mixture in the skillet, flatten with a large spoon or spatula, and cook until the bottom is crisp. Carefully turn and cook the other side until crisp. Serve warm.