In a food processor, combine dates, nuts, cinnamon, oil and salt. Puree until finely chopped and the mixture sticks together when pinched with your fingers. Turn out into a square baking dish (I used a 6 x 8 glass container).
Open the chilled coconut milk and without stirring, spoon out the cream layer into a medium bowl. With a fine mesh strainer, pour out the remainder of the can and keep all the cream that is in the top. Reserve the watery milk for another use.
Whip the coconut cream along with the powdered sugar, lemon zest, and vanilla. Pour atop the nut layer.
In the food processor, puree berries and chia seeds until smooth. Add stevia, sugar, or other sweetener to taste. Pour atop the cream layer, and chill in the refrigerator to set for at least 2 hours.