Place the chickpeas in a bowl, cover with cold water, and let soak overnight. The next day, drain the chickpeas and rinse well. Place them in a saucepan of unsalted cold water, bring to a boil, reduce the heat, and simmer for 50 minutes to 1 hour or until tender. Drain well and reserve in a large bowl.

Combine the garlic, walnuts, and herbs in the bowl of a food processor or blender. Pulse until finely chopped. Add the tahini paste and 4 tablespoons of the lemon juice and whizz to mix. With the motor running, add the olive oil in a thin steady stream until amalgamated.

Add enough water to make a thin dressing. Pour the sauce into a bowl and season to taste with salt, paprika, and some extra lemon juice if needed.

Add the potatoes to a saucepan of lightly salted boiling water and simmer for 15 to 20 minutes or until tender. Drain well, then cut the potatoes in half and add to the bowl with the chickpeas. Add the dressing and toss the mixture well while still warm.

Serve warm or cold, sprinkled with the chopped walnuts, toasted sesame seeds, and sprigs of fresh mint.