Preheat oven to 350 degrees. Line a 9 inch square pan with parchment paper so that there is an overhang on both sides.
In a large bowl, mix together the ground flax seed and the water. Let sit for a few minutes until it forms a gel.
Add the peanut butter and maple syrup and stir well. Add the gluten free oats, gluten free flour blend, baking soda, and sea salt. Stir until fully combined.
Stir in the chocolate chips.
Spread the mixture into the prepared pan.
Bake at 350 degrees for 25-29 minutes, or until a toothpick inserted in the center comes out clean.
Let the bars cool completely, then use the parchment paper to remove them from the pan. Slice into squares. Melt the ½ cup of chocolate chips and spoon into a pastry bag or a ziploc bag with the corner cut off. Drizzle the melted chocolate over the sliced bars.