Line a 9x9 square pan (for thicker bars like in the pictures) or a 9x13 rectangular pan for thinner bars with parchment paper or foil that has been lightly sprayed with cooking spray leaving an overhang over the pan for easy removal of bars.Add dates and water to a medium pot on medium low heat. Mash down with a fork and continue stirring and mashing while the mixture heats up. The dates should soften after about 3-5 minutes. Continue mashing and stirring until paste becomes smoother and uniform. It is okay to see some chunks still - as long as it is a uniform paste then it is ready to use.Make the granola barsOnce the date paste is smooth and softened, add peanut butter and coconut oil to the pot. Stir constantly to combine and remove from heat once the mixture is smooth and the coconut oil has melted (about 1 minute). Remove from heat and stir in vanilla extract.Pour in the oat flour, shredded coconut, ground cinnamon and salt (if using) and mix in gently.Toss in the rolled oats and flaxseeds and combine gently with a spatula or large spoon. Gently fold in half of the chocolate chips but make sure the mixture is completely cool or else the chocolate chips will melt.Pour granola mixture into prepared pan.Spread evenly and press down firmly using a flat spatula. Sprinkle remaining chocolate chips evenly. Press down firmly again with spatula or your hands to flatten and bind together. Chill in the fridge for at least 2 hours or overnight to set.Remove from the fridge and use the foil overhang to transfer the uncut bars to a cutting board. Using a sharp knife, cut into even rectangles.Store the bars in an airtight container in the refrigerator. If you have to stack them, be sure to use parchment paper or foil in between the layers, otherwise they'll stick together. Bars are best enjoyed straight out of the fridge since they tend to soften up at room temperature.