Preheat oven to 200 degrees C. Grease a 20x30cm baking dish.
In a frying pan over medium heat, heat the tuna oil. Stir in the onion and cook for 2 minutes. Stir in anchovy, garlic, oregano, chilli flakes and fresh chilli. Cook about 1 minute more.
Stir in tomatoes, olives and capers then simmer until thickened, about 10 minutes. Stir in tuna fish then remove from heat.
Layer the tuna mixture then the lasagne sheets about 4 times. Pour over the 1/4 cup of water then sprinkle with the cheese. Bake in preheated oven until cooked though and pasta is soft, about 30 minutes. Cool 10 minutes before serving.