Heat oven to 350 degrees. Pat chicken dry and season generously with salt and pepper.
Heat oil in a Dutch oven or heavy-bottomed skillet over medium-high until shimmering. Brown chicken pieces in batches, about 5 minutes per side, reducing the heat as necessary to avoid scorching, then transfer to a 9-by-13-inch (or similar size) ovenproof dish.
Reduce the heat to medium, add onion to skillet, season with a little salt, and sauté until softened and lightly browned, 8 to 10 minutes. Add garlic, bay leaf, chili, cumin and paprika, and stir.
Stir in wine and tomatoes, and bring to a boil, scraping the bottom of the pot. Pour sauce over chicken, tuck potato halves into sauce here and there, and cover. Bake until chicken is fork-tender and potatoes are soft, about 1 hour.
Pour sauce into a small shallow pan and bring to a brisk simmer. Let sauce reduce and thicken slightly, about 5 minutes. Pour sauce back over chicken and potatoes. Leave in sauce for as long as possible. Just before serving, sprinkle with freshly chopped cilantro.
