Heat your oven to 350 degrees.
In a small bowl, combine the flax with 3 tbsp. warm water, whisk with a fork, and set aside.
In a food processor, process the almonds into a fine meal. Add the oats, sugars, peanut butter, vanilla, and flax, and process until combined, about a minute.
Prepare 2 cookie sheets with parchment paper. Spoon the batter onto the paper, in about 1" balls.
Flatten with a fork, making a criss-cross pattern. Top each cookie with coarse sea salt.
Bake for 10 minutes, let cool, and enjoy!