Place a small saucepan on a high heat. Add the beans, clamp on the lid and cook for 1 minute. Stir and return the lid. Cook for another minute or until the beans are hot.

While the beans are cooking, drain the tuna. Chop the sun dried tomato.

When the beans are cooked, remove from the heat. Stir in the tuna, olives and tomato. Leave off the heat while you make the dressing.

Combine vinegar, mustard, oil and a pinch salt in a small bowl. Toss dressing into the beans. Serve warm.