Discard tough leaves and woody base of the lemongrass. Thinly slice the tender portion of the lemongrass stem.
In the base of a steamer, combine lemongrass, orange juice, lime juice and ginger; bring to a boil.
Arrange stingray on steamer rack or basket, fit to pan, and cover tightly. Reduce the heat and steam for 5 minutes or just until the stingray "flakes" easily when tested with a fork. If rack will not hold all of the stingray at one time, steam in two batches.
Using a wide slotted spatula, carefully transfer the stingray from the steamer rack to heatproof platter or individual serving plates; keep warm.
Turn up the heat to high and cook juices uncovered for 10 to 15 minutes or until it becomes sauce, reduced by about half (it should have the consistency of syrup).
Strain sauce over fish. Garnish with lime slices and chives.