Tuna and bean salad with mustard dressing

Method

1. Blanch the green beans in a pan of boiling salted water for 2-3 minutes until tender. Drain and refresh.
2. Put the chopped red onion in a sieve and run under cold water to remove some of the harsh flavour of raw onion.
3. Put the butter beans and the kidney beans in a bowl and stir in the green beans, onion, cherry tomatoes, rocket and tuna.
4. For the dressing whisk the mustard, honey, and the lemon zest and juice. Season, then whisk in the olive oil. Toss with the salad.