Tip the tuna and white beans into a sieve and drain well. That way the salad won't turn watery later.
Wash and quarter the cherry tomatoes. Finely dice the onion and roughly chop the parsley.
Loosely flake the tuna with a fork in a large bowl. Add the white beans, cherry tomatoes, onion and parsley.
Mix the olive oil with the lemon juice, salt and pepper. Pour the dressing over the salad.
Toss everything carefully so the white beans stay as whole as possible. Season again to taste with salt, pepper and lemon juice.
Serve straight away, or pack into boxes to take with you and keep well chilled.
Good to know
A salad like this is made for days when things need to be quick but should still taste like a proper meal. Fresh, generous and pleasantly uncomplicated.
Swaps
Tuna → tinned wild salmon (also provides protein and naturally contains omega-3 fatty acids). White beans → chickpeas (a little firmer, also contain fibre). Parsley → dill (fresh herby note, naturally contains vitamin K). Onion → spring onion (milder in flavour).
Allergens
Contains fish. White beans aren't among the most common allergens, but they don't suit every sensitive stomach. For children, serve the tuna finely flaked; in pregnancy, only eat tuna occasionally (mercury).