In a Dutch oven or large deep skillet heat coconut milk over medium-high heat until warm. Whisk in lime juice and fish sauce. Add shallot, garlic and chile pepper; bring to boiling. Boil 1 minute.
Add mussels; cover and cook 4 to 7 minutes or until mussels open fully. Remove pot from heat. Discard any mussels that did not open. Stir in lime zest. Spoon mussels and cooking liquid into individual bowls, sprinkle with cilantro, and serve.