Special equipment: Ten 3-inch tartlet pans, preferably with removable bottoms
For the crust: Process the rolled oats, almonds and salt in a food processor until finely ground. Transfer the mixture to a medium bowl, and stir in the oat flour and brown rice flour. Drizzle in the coconut oil, and mix well. Add the maple syrup and vanilla, then stir to combine. (The dough will be quite wet.) Cover the bowl, and set aside for 30 to 60 minutes or until the dough is moist but no longer sticky.
Preheat the oven to 350 degrees F. Thoroughly oil ten 3-inch tartlet pans, and press the dough evenly into each, trimming excess dough from the edges. Prick the bottoms with a fork several times, place the tart pans on a baking sheet and bake until golden and fragrant, 20 to 22 minutes. Let cool.
For the filling: Line a medium strainer with a thin kitchen towel or several layers of cheesecloth, and place it over a medium pot; set aside. Blend 2 1/2 cups water and the almonds in a blender until smooth. Pour the almond milk through the lined strainer into a pot. Gather the edges of the cloth, and gently squeeze out the milk; discard the dry pulp that remains. Add the maple syrup, agar flakes and salt to the almond milk, and whisk to combine. Bring the mixture to a boil over medium heat, whisking every minute or so. Cover the pot, reduce the heat to low and simmer until all the agar is dissolved, about 15 minutes. Combine the arrowroot with 1 tablespoon water, and slowly drizzle the mixture into the simmering liquid. When the liquid returns to a simmer, remove the pot from the heat and whisk in the vanilla.
Carefully remove the crusts from the pans. Pour 1/4 cup of the warm filling into each tart shell. Place the tartlets on a flat tray, set aside until the filling has stopped steaming, then refrigerate for at least 30 minutes or until ready to serve.
For the topping: Bring the cranberries, orange juice, maple syrup and cinnamon to a boil in a small pot. Stir the mixture, cover the pot, reduce the heat to low and simmer for until the cranberries are soft, 5 minutes. Dissolve the arrowroot in 2 teaspoons water, and slowly drizzle the arrowroot mixture into the cranberry mixture. Remove the pan from the heat once the mixture has returned to a simmer. Let cool. Top each tartlet with a spoonful of the cranberry mixture, and serve.
Although rolled oats do not contain gluten, they are processed in facilities that also process grains with gluten. So if you're making these for someone with a severe gluten allergy, be sure to use certified gluten-free oats and oat flour. Using freshly toasted almonds in these tartlets gives the best flavor. Spread raw whole almonds over a rimmed baking sheet in a single layer. Place in a preheated 300-degree-F oven, and bake for 18 to 20 minutes or until the inside is a shade darker. Let cool.