Remove the pits from the dates. Cover the dates with very hot water and let soak until very soft, 15 to 20 minutes.
Drain the water then add the dates to a food processor fitted with the metal blade. Add the beans, cocoa powder, salt, and vanilla.
Process the ingredients until smooth, stopping to scrape down the sides of the bowl a few times. (If the mixture is too thick or is not blending well, add a splash of water and continue to process until smooth.)
Taste the dip and add the maple syrup if you want it sweeter. If the dip doesn't have a lot of chocolate flavor, you might also want to add a pinch more salt (salt helps enhance the flavor of the dip).
Transfer the dip to an airtight container and store in the refrigerator for up to a week. Use as a dip for fruit, pretzels, graham crackers, etc. Or use a spread on sandwiches or roll-ups.