Place a wok over medium-high heat and add the coconut milk, chicken and fish sauce. Bring the mixture to a gentle boil. Turn the heat down and simmer, uncovered until chicken is no longer pink, about 15 minutes.
Using a slotted spoon remove the chicken from the wok. Place in a bowl, cover and set aside.
Return to heat and gently whisk curry paste into coconut mixture. Add the ginger and chiles. Return to a boil, decrease heat and simmer for 10 minutes to reduce slightly.
Return chicken to wok and bring to a simmer. Add remaining coconut milk and stir. Increase heat to medium-high and cook for 5 minutes.
Pour into serving dish and sprinkle with cilantro.