First, line either a 9x9-inch baking dish or a 9x13-inch baking dish with parchment paper. Really any size will work, but the smaller the dish, the thicker the bars will be.
Next, place Medjool dates, peanut butter, oat flour, honey, vanilla extract, and protein powder into a high-speed food processor.
Process on high for 2-3 minutes, stopping to scrape the sides as needed.
Add water by the tablespoon and continue to process on high until a cookie dough-like batter has formed and the Medjool dates have disappeared into the dough. You want your batter to be able to hold shape and be similar to cookie dough, but not be too runny. This is all dependant on how drippy your peanut butter is. You may need to use less than 1/4 cup or more than 1/4 cup of water.
Once your dough has formed, transfer it into a parchment-lined 9x9-inch square baking dish (for thicker bars) or a 9x13-inch baking dish (for thinner bars). Either work! Set aside.
Prepare chocolate topping by placing dark chocolate chips and coconut oil into a microwave-safe bowl. Microwave in increments of 15 seconds and stir until melted.
Pour chocolate topping onto protein bars and use a spatula to evenly spread it out. Then, sprinkle on coarse sea salt.
Place bars into the freezer to set for 30 minutes to an hour or until the chocolate has fully hardened.
Slice and store in the fridge for up to 7 days or in the freezer for up to 3 months.