Place hazelnuts on the same baking tray and bake for 15 minutes.
While hazelnuts are roasting, make the pie crust. Add salt to the food processor and process until fine crumbs form. Do not over process because nuts will begin to turn into a nut butter. Add Medjool dates, coconut oil and almond milk; process until combined. “Dough” should stick together when squeezed between fingers.
Line a pie dish with 2 thin pieces of parchment paper crosswise (for easier pie removal) and transfer “dough” mixture on top. Using your fingers flatten it into a pie crust. Make sure to press sides well and even make a nice edge. Set aside.
In a food processor (no need to rinse), add 2 cups of roasted hazelnuts and process until nut butter forms. At first you will see ground nuts, then wet ground nuts and finally a paste. You will have to stop and scrape the sides of the bowl a few times. Add coconut milk, sugar, cacao powder, vanilla and salt; process until very smooth.
Pour into prepared pie crust and sprinkle with crushed hazelnuts (if desired). Freeze for at least 4 hours or overnight. To serve, let pie thaw on a counter for 45-60 minutes, remove from the pie dish holding onto parchment paper flaps and cut into 12 slices. Serve immediately. P.S. It helps a lot to cut up the pie right away and defrost slices vs. the whole thing and cut again etc.