Preheat oven to 350°F. Grease 8 cups of a standard 12-cup muffin pan.
In a small saucepan, combine teff and water. Bring to a boil over medium-high heat. Reduce heat to low, cover and simmer, stirring occasionally, for 12 to 15 minutes or until water is absorbed. Remove from heat and let stand for 5 minutes. Uncover and fluff teff with a fork.
In blender, combine dates, cocoa, espresso powder, salt, milk and vanilla; purée until smooth.
Transfer date mixture to a large bowl and stir in cooked teff, flax seeds and chocolate chips.
Divide batter equally among prepared muffin cups.
Bake in preheated oven for 25 to 28 minutes or until firmly set. Let cool completely in pan on a wire rack.