2 large or 3 medium tomatoes, cut into large pieces (about 3 cups)
1 large onion, peeled and cut into quarters (about 1 1/2 cups)
2 jalapeño peppers, stem removed, cut in half lengthwise
6 tablespoons vegetable oil, divided
Kosher salt
2 large or 3 medium sweet potatoes, peeled and cut into a small dice (about 3 cups)
1 teaspoon ground cumin
1 teaspoon chili powder
1/2 teaspoon ground coriander
2 medium garlic cloves, crushed
1 canned chile en adobo, finely chopped (about 1 tablespoon chili and sauce)
1 tablespoon red wine vinegar
15 small corn tortillas
2 (15 ounce) cans black beans, rinsed and drained
4 green onions, white and green parts, thinly sliced
1 cup shredded cheddar cheese
1 cup shredded Monterey Jack cheese
1 avocado, pit removed, sliced
1 lime, cut into wedges
Sour cream, for serving
Chopped cilantro, for serving