How to Make It
Rinse and sort beans according to package directions. Heat canola oil in a large skillet over medium-high. Add onion, bell pepper, and, if desired, bacon; cook, stirring occasionally, until onions are tender, about 8 minutes. Add garlic, and cook, stirring often, until fragrant, about 30 seconds.
Transfer onion mixture to a 6-quart slow cooker; add beans, jalapeño, chicken broth, 1 1/2 teaspoons salt, brown sugar, cumin, pepper, and oregano. Cover and cook on LOW until beans are tender, about 6 hours.
Boil apple cider vinegar, water, granulated sugar and 2 teaspoons salt in a small saucepan over medium-high until sugar and salt dissolve, 3 to 5 minutes. Pour vinegar mixture over red onion in a medium bowl; cover and chill at least 30 minutes.
Toss together jicama, mango, avocado, diced jalapeño, 2 tablespoons cilantro, lime juice, olive oil, and 1/2 teaspoon kosher salt in a medium bowl. Lightly mash 2 cups drained cooked black beans, chipotle pepper in adobo, and 1/4 teaspoon kosher salt; spread mixture on corn tostada shells. Top with mango mixture and 1/4 cup pickled red onions. Sprinkle tostadas with queso fresco and 1 Tbsp. chopped fresh cilantro.