Mediterranean tuna salad

Ingredients (serves 4): 1 baby lettuce, leaves torn 200g cocktail tomatoes, halved 1 small onion, halved, thinly sliced 1 English cucumber, cut into 2cm cubes 1 green bell pepper (capsicum), cut into 2cm cubes 2/3 cup drained feta cheese 2/3 cup pitted Kalamata olives 2 tablespoons chopped fresh oregano 2 x 185g cans Tuna in Olive…