Zest your lemon into the bowl of a food processor or blender. Add the oregano leaves, half the garlic clove, a pinch of salt, 2 tbsp olive oil and 2 tbsp lemon juice.
Whiz into a delicious dressing. Taste. Tweak as needed. No kit? Finely chop your oregano; whisk with the remaining ingredients. Put the dressing to one side.
Pop the tahini in a large bowl. Whisk with a pinch of salt, 1 tbsp lemon juice and 2 tbsp water. Taste. Add a little garlic or more lemon, if you like.
Drain the beans. Rinse well. Quarter the cucumber. Thinly slice it. Halve, peel and thinly slice your onion. Pop your onion in a sieve. Pour boiling water over - just enough to rinse. This will soften and sweeten the onions a little.
Fold the beans, cucumber and onions into the tahini dressing. Taste. Add a pinch of chilli flakes if needed, to taste. Finish with the oregano dressing drizzled and more chilli (if you like) over the top.