In a food processor, puree the dates until they reach a gummy ground consistency. Add in the tahini, coconut oil, vanilla and salt. Puree until smooth and set aside.
Place the chocolate and coconut oil into a medium sized glass bowl and set it over a small pot filled 1 inch up with water. Bring the water to a simmer and slowly stir the chocolate until it melts. Once melted, remove the bowl from the heat, and set aside. Optional microwave method: Place the chocolate and coconut oil in a microwave safe dish. Melt in the microwave on 50% power in 30 second increments until just melted (a few tiny pieces left unmelted is fine- they’ll melt in seconds outside of the heat).
Using a small spoon, carefully spoon a thin layer of the dark chocolate onto the bottoms of 10 regular sized silicon muffin containers or 50 very miniature silicon molds. Place the molds onto a baking sheet and transfer to the freezer to harden for at least 5 minutes.
Once set, make a ball of the filling smaller than the diameter of the muffin or candy mold and press it on top of the chocolate base, being careful not to touch the sides of the mold but also to try to make as flat a surface as possible. If using a regular sized mold, I recommend about a tablespoon and a half of filling, and if using the mini candy molds, about ½ teaspoon.
Using a small spoon, very gingerly pour the chocolate down the sides to envelope the filling and on the top to fully cover the peanut butter. Transfer to the freezer to fully set, at least 20 minutes.
Right before serving, sprinkle the cups with a pinch of fleur de sel.