Turkey Barbacoa Tacos with Black Beans

Toast sesame seeds in a dry large skillet, preferably cast iron, over medium heat, stirring, until golden, about 3 minutes. Transfer to a blender.
Place skillet over medium-high heat and add tomatoes, garlic, and 4 onion halves and cook, turning often, until softened and charred in spots, 5-8 minutes. Transfer tomatoes to blender; set onions and garlic aside.
Cook chiles in same skillet, turning often, until darkened and fragrant, about 1 minute. Add to blender. Once cool enough to handle, peel garlic and onion and add to blender along with 1 tablespoon salt. Blend until smooth.
Divide drumsticks between 2 resealable plastic bags. Add tomato purée, dividing evenly. Seal bags, pressing out air, and toss to coat. Chill at least 12 hours.
Preheat oven to 325°. Line a large roasting pan with banana leaves, then individually wrap drumsticks with the marinade (use all of it) in banana leaves; place in pan. Cover with any remaining leaves, then cover pan tightly with foil. Bake until meat is very tender and falling off the bone (tear into packets with a fork to check), 2-2 1/2 hours. Let cool slightly.
Meanwhile, drain beans and combine with carrots, celery, cumin, and remaining onion halves in a large pot. Add water to cover by 2"; season generously with pepper. Bring to a gentle simmer and cook, partially covered, seasoning with salt halfway through, until beans are tender, 80-90 minutes. Pluck out carrots, celery, and onion.
Transfer drumsticks and any marinade to a large bowl; discard banana leaves. Pour turkey cooking liquid from roasting pan into a large glass measuring cup; season sauce with salt.
Scrape off cooked marinade from turkey legs, then shred meat into bitesize pieces; discard skin, bones, and sinews. Combine shredded meat with marinade; season with salt if needed.
Serve turkey with tortillas, salsa, queso fresco, and small cups of sauce. Serve beans with some of their liquid.