Trim the root ends of the leeks. Cut off and discard the upper green parts, about 2 inches above the white bulbs. Make a slit along one side of each leek.
Rinse the leek well under cold running water to remove any sand that has lodged in the layers. Slice them into 1/2 inch lengths. Place into a bowl.
Place the spinach and the rice into separate bowls. Combine the soy sauce, lemon juice and zest in another bowl. In the last bowl, combine the ginger, garlic and onion.
Heat a nonstick wok or large heavy bottomed skillet over high heat for 2 minutes. Add the oil then the onion mixture. Stir-fry for 30 seconds.
Add the leeks and stir-fry for 1 minute. Add the spinach and stir-fry for 1 1/2 minutes.
Add the rice and stir-fry for 1 minute to heat through. Use a spatula to break apart the cold rice into smaller pieces while you stir-fry.
Add the soy sauce mixture and stir to combine. Add the cilantro and stir well. Remove from wok and serve.