In a large oven dish, mix the tuna with the crushed tomatoes, add salt, pepper and herbs of your choice (parsley, basel or dill for example). Then slice the courgettes and aubergines and layer them on top of the tuna and tomatoes mix, adding a bit of olive oil in between layers.
Put in the oven at 200°C for 30 minutes, take out of the oven and sprinkle a bit of grated cheese on top, put back in the oven for another 10 minutes. Serve hot.