You will need a dehydrator with at least 4 trays. I'm sure there's a way to do this in the oven or even outside, but I only know the dehydrator.
Rhubarb Fruit Leather
8 cups of chopped rhubarb
2 VERY ripe red skinned pears (I'm sure the regular yellow/green would work - just won't be as pretty)
3 tablespoons or to taste of agave
Core your pears and put them into your food processor.
Steam your rhubarb, 4 cups at a time, for 7 minutes then put into processor with pears.
Puree it all together, adding agave towards the end.
Using either the liners that come with the dehydrator or cut out wax paper circles to make your own liners, glop the puree on (about a coup per tray). Spread out as evenly as you can, you don't want thick or thin spots.
Set the temperature for 110 F and walk away for 12 - 13 hours.
The fruit leather is done when it is no longer sticky.
Peel off of the liners and cut into wedges. Can be stored in the fridge for a really long time.
*NOTE*after steaming your rhubarb you will be left with a watery syrup in the pan. Reduce it down until is is more a more syrupy consistency and use to flavor ice water or sweeten it up to make a tasty syrup for brunch pancakes.