Drain the beans and put them in a mixing bowl.
Put the chopped cavolo nero in a steamer and steam over boiling water for 3-5 minutes. Alternatively, blanch them in boiling water for 3 minutes, then drain.
Whilst the cabbage is cooking, tear or cut the sundried tomatoes into thin slices and add them to the beans. Finely chop the spring onions and add them to the beans.
Add the oil, vinegar, minced garlic, lemon zest & juice. Season with salt & pepper.
Rinse the cooked cavolo nero under cold water, then drain and add to the bean salad.
Toss well and serve.