I don’t know about salty recipes with rhubarb, but I had rhubarb yesterday for dinner in the form of a pie with buckwheat flour. For the dough, I mixed buckwheat flour with water and salt, made a dough out of it and then spread it like a pizza dough (which was tricky). Instead of chopped hazelnuts I put some oat bran on the dough. Then I cut the rhubarb and put it on top of the oat bran, and finally I poured a mixture of kefir, two eggs, two tablespoons of buckwheat flour (to bind), vanilla, cinnamon, and ginger over the pie and baked it in the oven. I make it without stevia but if you want it sweet, you can add that to the mixture.
The taste is different than normal pie because of the buckwheat flour, but I still loved it.
I remember once making coconut/buckwheat bread muffins with rhubarb, stevia and lemon juice, and they came out really well, so once you can tolerate coconut flour you could try that…