Preheat oven to 300 °F;. Line an 18 by 13-inch rimmed baking sheet with parchment paper. Set pan aside. In large bowl, toss together oats, almond flour, brown rice flour, and salt. Pour canola oil evenly over the mixture. Stir with a wooden spoon to coat mixture evenly with oil.

Combine maple syrup and dark brown sugar in a medium pot. Warm mixture over medium heat until the sugar dissolves, about six minutes. Gently stir the mixture frequently. Remove pot from the heat. Add vanilla extract. Stir to combine.

Pour sugar-mixture over oat-mixture. Stir with a wood spoon to combine. At first, the granola will be thick and sticky. Continue stirring, breaking up an lumps of sugar/oats with the back of the wooden spoon, until the sugar-maple is evenly distributed.

Press mixture very firmly into prepared pan. Bake until golden brown and aromatic, about 45 minutes. Remove pan from oven. Immediately score granola into bars. (The granola might break into smaller pieces when scored. This is fine.) Allow granola to cool. "Snap" bars into bite-size nuggets. Store granola in a covered container for up to two weeks.