Mix the coconut cream powder and the warm water together. Spoon a bit of the liquid into the cornstarch to liquefy, and then add back into the coconut milk mix. Add sugar and salt and bring to a boil. If lumps form for any reason, strain them out. Cool mixture and use in your ice cream maker.

You can also do the poor man's freeze ice cream where you freeze, scrape, freeze, scrape like granita but the texture is not going to be as nice as the ice cream machine.