While the rice cooks, prepare the rest of the dish.
Combine all the marinade ingredients in a small bowl and then add shrimp, just before skewering. They should only sit in the marinade about 15 minutes or so. Anymore and I think they get mushy. I threaded mine on wooden skewers which had been soaked for at least 30 minutes, beginning with a key lime half and ending with a key lime half. Place on a hot grill until pink and opaque.