Boil the eggs for about 8 minutes until soft. Quench, peel and let them cool down
Drain the tuna and pluck it finely. Wash and chop the oregano. Peel and finely chop the onion. Add both to the tuna. Stir in mayonnaise, yoghurt and lemon juice. Season to taste
Wash the cucumber and cut into thin slices. Remove the crusts from toast. Cut eggs into slices. Spread tuna cream on 8 slices of toast
Cover tuna toasts with cucumber and 4 with egg. Put together one egg toast, one cucumber toast and one uncoated toast. Cut the tramezzini diagonally in half and garnish with lettuce leaves if necessary