Preheat the oven to 350°F and line a couple of baking sheets with parchment paper.
In a large mixing bowl, whisk together the oat flour, oats, spirulina, cinnamon, baking soda, and salt.
In a separate large mixing bowl, use a fork or potato masher to mash the bananas.
Stir the oil, maple syrup, and vanilla into the bowl with the mashed banana.
Add the oat mixture to the bowl with the banana mixture, and stir everything well until a soft dough forms.
Stir the raisins and walnuts into the dough.
Drop the dough by rounded 1 ½ tablespoonfuls on the baking sheets, then flatten each cookie slightly.
Bake the cookies for 10 to 12 minutes, until lightly browned.
Place the baking sheets on cooling racks when they come out of the oven. Let the cookies cool until set, then remove them from the baking sheets and transfer them directly to the cooling racks to finish cooling.
Serve.