In a large saucepan, heat oil over medium-high heat. Add onion, ginger, and garlic; cook for 4 minutes. Add rice; cook for 1 minute, stirring constantly. Stir in coconut milk, 1½ cups water, cilantro, salt, and zest; bring to a boil. Cover, reduce heat, and simmer until rice is tender and liquid is absorbed, 15 to 20 minutes.

Remove from heat, and let stand for 5 minutes. Fluff rice with a fork. Garnish with cilantro, if desired.