In a nonstick skillet over medium heat, toast the oats, stirring often, until they start to brown. Cool.
In a large bowl, combine cooled oats, brown sugar, salt, vanilla, coconut oil, and almond flour. Mix well.
Spray 4 (4 1/2-inch) mini-tart pans with cooking spray and place them on a baking sheet that has been lined with parchment paper. Scoop about 1/4 cup of the oat mixture into each tart pan. Carefully press the mixture up the sides of each pan, adding more if necessary. Fill bottom of the pans with remaining mixture and press down. (You want the entire inside surface of the pans to be covered.) Carefully remove the tart pans and dump anything that has spilled on the parchment. Replace the parchment and the tart pans on the baking sheet and refrigerate while you make the filling.
Mix chia seeds and water in a small bowl. Refrigerate for about 15 minutes.
In a large bowl, combine peaches, almond flour, cinnamon, ginger, and nutmeg. Add chia seed gel. Mix well and let the filling sit for 30 minutes at room temperature.
Preheat the oven to 375°F. Add 1/4 of peach mixture to each tart pan. Bake for about 20 minutes or until the peaches are soft. (Check after 15 minutes to see if the edges are getting too brown; if they are, cover with foil for the remaining time.)
Remove from pans and serve with whipped cream, if desired. The tarts will be easier to remove from the pans if you let them cool first.
SHORTCUT: This recipe works equally well as a crumble. Make the same amount of filling, but cut the crust ingredients by half. Place the filling in a 7- x 5-inch baking dish that has been sprayed with cooking spray. Top with crumbled crust mixture and bake 15 to 20 minutes at 375 degrees F or until the crumble is bubbly in the corners.