Sort and wash chickpeas; place in a large Dutch oven. Cover with water to 2 inches above chickpeas; cover and let stand 8 hours. Drain chickpeas.
Place 1 1/2 cups chickpeas, 4 cups water, 1/2 cup onion, garlic, and bay leaf in pan; bring to a boil. (Reserve leftover chickpeas for another use.) Cover, reduce heat, and simmer 45 minutes or until beans are just tender. Drain chickpea mixture in a colander over a bowl, reserving 1/2 cup cooking liquid. Set chickpea mixture aside.
Heat oil in pan over medium-high heat. Dredge chicken in flour. Add chicken to pan; cook 6 minutes, browning on all sides. Remove from pan.
Add remaining 1/2 cup onion to pan. Sauté 4 minutes or until tender. Add vinegar, scraping pan to loosen browned bits. Cook 1 minute or until liquid evaporates.
Add 2 cups tomato, Homemade Chicken Stock, and reserved cooking liquid to pan. Add chickpea mixture, and bring to a boil. Place chicken on top of chickpeas, and sprinkle with 1/2 teaspoon salt and 1/2 teaspoon black pepper. Cover, reduce heat, and simmer for 40 minutes or until chicken is done and chickpeas are tender. Discard bay leaf. Serve with lemon wedges, if desired.
Wine note: Budget wines are always in order (see our list of favorites in this issue's Wine Tasting, page 258). In particular, one of our choices is beautifully suited to this dish. The REDS 2005 from Sonoma California--just $9 a bottle or $80 a glass--has beautiful boysenberry fruit flavors and just the right umph to go with this flavorful dish. --Karen MacNeil