This dish is so easy to make and can be enjoyed all year round. It can be served as a side dish, but I prefer it on its own. Once the flavours are married, it tastes sensational, so make it a day in advance to increase their intensity.
1 Place beans in a large bowl, cover with water and soak for 5 hrs or overnight.
2 Drain beans and rinse well. Place in a large saucepan and add onion, celery, carrot, garlic, rosemary and bay leaf. Cover with water and bring to boil on high heat. Reduce heat to medium and cook for 40-45 mins, until beans are tender. Drain, discarding vegetables and herbs.
Place beans in a bowl. Add tuna, red onion and oil. Season and toss to combine. Stand for 10-20 mins to allow flavours to infuse.
Scatter over oregano and serve with toasted ciabatta slices.