In a large or Medium Ziploc® Zip 'n Steam™ Bag, combine chicken, beans, spinach, lemon juice, olive oil, rosemary, pepper flakes and salt. Seal bag and shake gently to combine ingredients. Pat ingredients into single layer. Place bag in microwave oven.
Cook on full power for 6-1/2 minutes (Medium bag) or 5-1/2 minutes (Large bag) or until meat is no longer pink. If needed, continue microwaving at 30-second intervals until done.
Allow bag to stand 1 minute before handling. Shake bag to distribute seasonings. Carefully open bag and remove contents. Garnish with Parmesan cheese and tomatoes if desired.