Combine rhubarb, water, and salt in a medium saucepan over medium high heat; bring to a boil, stirring occasionally. Reduce heat to medium low; simmer, stirring occasionally, until rhubarb has broken down, 6 to 8 minutes. Stir in honey; cook and stir until mixture has thickened, 2 to 3 minutes.
Arrange five 12 to 16 ounce jars on a work surface. Place 2 tablespoons rhubarb mixture in the bottom of each jar; top each with 2 tablespoons graham cracker crumbs and each with ⅔ cup yogurt, in that order. Divide remaining rhubarb mixture and graham cracker crumbs among parfaits; top each with 1 tablespoon walnuts.
Seal jars; refrigerate until ready to eat.
Make-Ahead Rhubarb Yogurt Parfaits · Dinner Match Lab | Dinner Match Lab