Roast the cumin in a dry frying pan. Grind it into powder. Grind the sesame into flour.
Squeeze the lemon juice. Peel the garlic.
In a blender, whisk together sesame flour, garlic, lemon juice, olive oil and a little salt. Add some of the cooked chickpeas and cumin. Gradually add all the chickpeas and, if necessary, the water they were cooked in.