Preheat oven to 350º and adjust the racks so you can easily manipulate 2 baking trays.
Pulverize flaxseed in a clean coffee grinder or with a mortar and pestle. Pop the flax in a small bowl and add warm water, stir, and set aside.
Blitz 4 cups of oats in the food processor until you get a nice flour consistency. Remove the oat flour to a large bowl and set aside.
Add the pineapple, flax, and melted coconut oil to the food processor and pulse lightly to combine. Add the flour by cupful until dough ball forms.
Transfer the dough ball to your floured work surface. Flatten the ball out with your hands and sprinkle your chopped dried fruit over top. Knead the dough, splitting and folding as necessary to spread the fruit out evenly.
Roll your dough, adding flour as necessary to keep it workable. Cut out shapes and place onto cookie sheets.
Bake the cookies for 20 minutes, then pull out, brush with either milk or a beaten egg for some shine, and rotate trays.
Bake another 20 minutes or until most of the way crisp, then turn off the oven and leave cookies inside to dry out a bit more.
Transfer to cooling rack and let it cool down before serving.