Pat chicken dry; season well with salt and pepper. Warm oil in a large, deep skillet over medium-high heat. Working in batches, brown chicken for 3 minutes on each side. Transfer to a large plate.
Drain all but 1 Tbsp. fat from skillet. Add onions, reduce heat to medium; sauté until soft and beginning to brown, about 10 minutes. Add garlic, red pepper and thyme; stir for 30 seconds. Pour in wine; bring to a boil, scraping brown bits off bottom of pot. When wine has almost evaporated, add tomatoes and bay leaf.
Reduce heat to medium-low and add chicken and any juices. Turn pieces in sauce, partially cover and simmer, basting occasionally, until chicken is cooked through and tender, about 45 minutes. Season with salt and pepper.
Make it ahead
TO FREEZE: Let cool. Put in a freezer-safe container (leave 1/2 inch of space at the top); freeze.
TO SERVE: Thaw in refrigerator overnight. Reheat in a covered pot over medium heat, turning occasionally, until warm, 30 minutes.