Boil the beluga lentils in a little water until soft, place in a sieve and drain well.
In the meantime, wash the lemon / lime and finely grate the peel. Squeeze out the juice and set aside. Finely grind the cumin and coriander seeds.
Put the beluga lentils with the grated lemon / lime zest and some juice in the blender. Season with cumin and coriander, add a little rapeseed oil and puree everything until a fine mixture is formed. Season to taste with pepper and salt, possibly add a little lemon / lime juice.