Cuban Style Black Beans

Name: Cuban-Style Black Beans
Ingredients: 1 pound dried black beans, picked through, rinsed; 1 bay leaf; 1 medium onion, finely chopped, divided; 1 green bell pepper, seeds and ribs removed, finely chopped, divided; 8 garlic cloves, finely grated, divided; 5 teaspoons Diamond Crystal or 1 tablespoon Morton kosher salt, plus more; 1 teaspoon dried Mexican or Italian oregano, divided; ¼ cup extra-virgin olive oil; Freshly ground black pepper; Cilantro leaves with tender stems (for serving; optional)