- Drain the can of tuna and set aside. Drain the beans and rinse if need be. Leave to drain.
- Thinly slice the small red onion into half moon shapes. Finely chop a handful of flat leaf parsley.
- Whisk together the olive oil, lemon juice, lemon zest to make the dressing.
- Combine the tuna, beans, onion and half of the herbs with the dressing.
- Serve on a bed of red oak leaf lettuce or lollo rosso, with the remaining herbs sprinkled over.