Put the chickpeas in a large bowl and add enough cold water to cover them by at least 2 inches. Let soak overnight, then drain.
Place the drained, uncooked chickpeas and the onions in the bowl of a food processor.
Add the parsley, salt, garlic, and cumin. Process until blended but not pureed.
Add in the baking powder and 4 tablespoons of the flour, and pulse.
Turn into a bowl and refrigerate, covered, for several hours.
Form the chickpea mixture into balls about the size of walnuts, roll them in some sesame seeds, and bake them in the oven for about 15 minutes at 180 degrees celsius.