Chop the rhubarb, throw it in a big bowl, and layer with the right amount of sugar. Reverse osmosis pulls the juice out into the sugar and you end up with a nice syrup. No boiling so reduced the pectin-related hazes that rhubarb can produce.
You may need a bit of gentle warming to dissolve all the sugar, wash the pulp into your ferment vessel, add the yeast and off it goes. Very simple recipe.
If you haven't got it, I heartily recommend First Steps in Winemaking by C J J Berry, he's no longer with us, but I'm not sure if the book's still around.