Place tomatoes in a blender or a food processor fitted with the metal blade and process until liquefied. Set aside.
Heat oil in a large saucepan or stockpot over moderate heat. Add onion and saute until soft, about 10 minutes. Add garlic and saute for another 2 minutes. Add cumin, oregano and bay leaf and stir to combine. Sprinkle chicken pieces with salt and pepper and add to pan. Brown the chicken lightly. Add the tomatoes and enough water to cover 3/4 of chicken. Bring to a boil, cover, reduce the heat, and simmer for 45 minutes to 1 hour, until chicken is cooked through. About 10 minutes before the chicken is done, add the green pepper and peas. Serve warm.
