In a food processor, combine the pecans, dates, cacao powder, cinnamon, salt and coconut oil. Process, scraping the sides occasionally, until the mixture is very finely chopped and sticky (it might take a few minutes). Scrape the mixture into a tart pan with a removable bottom, pressing it firmly and evenly over the bottom and up the sides. Do Ahead: The crust can be covered with plastic wrap and refrigerated overnight.