Heat two cups of water in a saucepan till warm (not scalding hot). Place the dates in a bowl and submerge them with hot water. Allow them to sit for 15-20 minutes.
Drain the dates, reserving the soak water. Place them into a blender with 3/4 cup of the soak water, the vanilla, the coconut oil, and the salt. Blend them on a high speed till they are very smooth and resemble a sauce. Add more water as needed, until the sauce is thick but pourable (I used a scant cup).
Sauce will keep in an airtight container in the fridge for up to 5 days.