In a medium bowl, mix together the raspberries, rhubarb, sugar, and salt. If your raspberries are not sweet, you might consider adding another 2 tablespoons or 1/4 cup of sugar. Set aside.
Use a food processor to grind the Cracklin' Oat Bran into a powder that resembles oat bran. In a medium bowl, mix this with the walnuts and pecans. Using your fingers, work the butter into the dry ingredients until you have clumps.
Dump the fruit into a 9- or 10-inch ovenproof skillet or baking dish. Top with the Cracklin' Oat Bran crumble. Bake for 30 to 40 minutes, until the fruit is bubbling and the top is golden-brown and crisp.