Vegetable Stew

3 tablespoons olive oil
1 large yellow onion, diced
1 large red bell pepper, diced
1 tablespoon Kosher salt, plus more to taste
1/2 teaspoon freshly ground black pepper
3 cloves garlic, minced
3 carrots, sliced
2 teaspoons dried Mexican oregano, or regular oregano
2 chipotle peppers in adobo, diced
3 cups chopped green beans
1 cup dried black beans, rinsed
1 tablespoon tomato paste
2 cups diced sweet potato
1 (29-ounce) can crushed fire-roasted tomatoes
4 cups vegetable stock
8 corn tortillas
chopped cilantro, for garnish