Black Bean And Sweet Potato Tacos

Name: Black Bean And Sweet Potato Tacos
Ingredients: 2 sweet potatoes (really orange-fleshed yams), peeled and cut into small cubes; 1 tablespoon olive oil; salt and red chili flakes to taste; juice of 1 lime; 2 heaping cups shredded cabbage (I used a combination of purple and green cabbage); 1/4 cup finely diced yellow onions; 2 heaping tablespoons chopped cilantro; juice of 2 limes; 1 teaspoon olive oil; 1/4 cup finely diced yellow onion; 1 teaspoon ground cumin; 1 (15-ounce) can black beans, drained and rinsed; small corn tortillas