First, make the date/peanut butter filling. In a food processor (or blender), add the pitted dates and peanut butter. Blend until mixture becomes thoroughly combined. Place into a bowl and set aside.Line your miniature muffin liners out on a plate or serving dish.Place a small to medium pot over medium-high heat and add water. Place a heat-safe bowl on top (you do not want the bowl immersed in the water, just sitting on top on the pot). This is creating your own double boiler, if you have one, use this instead! Once the water is almost to a boil, add the chocolate and coconut oil. Stir until chocolate has melted.Using a teaspoon measuring utensil (or a small spoon), place a teaspoon of the melted chocolate into each miniature muffin liner. Once you have a bottom layer, place a teaspoon of the date/peanut butter filling on top. Then add one more teaspoon of the melted chocolate to each muffin liner, creating a top layer.If desired, sprinkle sea salt on top each peanut butter cup.Place in the freezer for at least 30 minutes.Store in the refrigerator or freezer. They will begin to melt at room temperature.