Wash chicken and pat dry. Heat 4 Tbsp. peanut oil in a large pot over high heat. Brown the chicken on both sides, working in batches if needed. Remove the chicken and set aside.
Add the remaining oil and turn down the temperature to medium-low.
Add the onions and saute until golden.
Add the tomato puree, tomato paste, garlic, green onions, ginger, red pepper flakes, salt and water and mix well.
Return chicken to the pot and mix again. Turn heat to high, bring to a boil, then reduce heat to low, cover, and simmer for 20 minutes.
Remove 1 cup of sauce from the pot and mix with the peanut butter. Return mixture to pot and mix well.
Cook uncovered for an additional 10 minutes or until the chicken is done.