Put 2 tsp cumin seeds in a dry frying pan over a medium heat. Toast for 2 mins, shaking the pan, till they pop and smell fragrant. Tip into a bowl. Pour the sesame seeds into the pan and toast for 2-3 mins, shaking the pan, till golden. Tip into the cumin bowl.
Halve your avocado. Scoop out and compost the stone. Carefully scoop out the flesh. Cut half into thin slices. Roughly chop the other half.
Zest and juice the lime. Tip into a food processor with the chopped avocado and the tahini. Pour in
2 tbsp water and 1 tbsp oil and season. Blitz to a smooth cream. No food processor? Slice the avocado and save for later. Whisk the tahini, oil, water and lime with a fork to make the dressing.
Halve the cherry tomatoes. Tip them into a large serving bowl.
Pick out any thick, tough stems from the watercress. Add the tender leaves to the tomatoes. Use a veg peeler make cucumber ribbons. Finely chop the seeded core. Add them both to the bowl.
Throw in the mixed bean sprouts and the sliced avocado. Add half the toasted cumin and sesame seeds. Toss gently to mix.
Pour in the avocado and tahini dressing (add the sliced avocado, if you didn’t use a food processor). Gently stir to coat in the dressing. Scatter over the remaining seeds and serve.