Bring water, cane juice, lemon peel, vanilla seeds and pod to a boil in a pot that will accommodate the rhubarb. Reduce heat to a simmer and cook for 10 minutes. Add rhubarb and simmer until just tender, about 3 minutes. Transfer to a stainless steel bowl and set bowl in an ice bath. Stir carefully with a rubber spatula until rhubarb is cooled completely.