Prepare the cherry chia jam: In a medium saucepan, bring the water and cherries to a boil over medium-high heat. Mash the cherries (you can leave a few pieces). Reduce heat to low-medium. Stir in the chia seeds and vanilla and let simmer, covered for 15-20 minutes or until the juices have been absorbed, stirring occasionally.
Meanwhile, preheat oven to 325°F. Grease a 9×9 inch glass dish with vegan butter. Set aside.
Spread the walnuts on a baking sheet. Toast the walnuts for 8-10 minutes or until lightly golden and fragrant. Remove from the oven and increase to 350°F.
Add the toasted walnuts, dates, 2 cups of oats, melted vegan butter, maple (or water), vanilla and salt to a food processor and process until combined. The mixture should easily stick together when pressed. If it remains too crumbly, add water, 1 tablespoon at a time until it sticks together. Add the remaining 1 cup of oats and process for a few seconds.
Press the crumble mixture at the bottom of the greased dish, leaving 1 1/2 cups for topping. Spread the cherry chia jam evenly, then top with the remaining crumble mixture.
Bake for 15 minutes, uncovered at 350°F. Let it cool completely before cutting. The bars will be delicate when warm. Serve the bars with your favorite ice cream.