First, be aware that your hands and equipment will stain when making turmeric paste, so plan around that. If using turmeric powder, skip to step 3. If using the fresh roots, carefully wash and then dry all your pieces of turmeric and ginger, checking for mold, and then peel each piece with a spoon.
Chop the roots into small pieces, and then add them to a very high-powered blender along with the coconut oil and sea salt. If needed, you can add the water while blending, but I highly recommend waiting since oil & water don't always mix well (especially in a cold house!).
Put your turmeric, ginger, coconut oil, and salt mixture into a small saucepan and add the water. Then heat everything on low for about 7-10 minutes. I recommend setting a timer, because although you need to heat the fresh turmeric a bit to make it more bioavailable, you don't want to overheat it.
Stir in the fresh-ground black pepper and simmer it all for one more minute, then let your golden paste cool before jarring it.