Parboil the potatoes
Boil the potatoes and beans in boiling salted water for approx. 15 mins. until just soft. Remove, refresh the beans in ice-cold water, drain. Cook the eggs in the same salted water for approx. 8 mins., leave to cool.
Mix the tomatoes, olives and beans with the oil, place in a grill tray. Mix the peppers, onion and boiled potatoes with the oil, season with salt.
Cover and grill the vegetables and potatoes over/on a medium heat (approx. 200 °C for approx. 15 mins. all over.
Brush the tuna steak with the oil, grill over/on a very high heat (approx. 250 °C for approx. 1 min. on each side. Cut the fish into slices, season.
Combine the vinegar, oil and garlic, season. Add the cucumber, anchovy fillets and grilled vegetables, mix. Peel the eggs, quarter and arrange on top of the salad along with the tuna.