Soak the beans in water overnight; then boil; yet be sure to keep the cooking liquid.
Blend the beans to make a creamy puree. Add the juice of the lemon and 2 tablespoons of the cooking water, a little at a time, to the blender. Add the tahini and garlic; continue to blend while adding a bit of salt. Transfer to a bowl; add oil; dust with paprika and true parsley. To make tahini paste at home, toast sesame seeds for 5 minutes in a pan (anti-stick), stirring a few times with wooden spoon, and being careful not to let the seeds burn. Place in a food processor; add oil; puree until smooth and creamy.