The tuna and harissa sandwich is a well established Libyan tradition. Chilli paste (harissa) spices up a plain tuna sandwich into something else, and the two definitely go hand in hand. But that's not the only option. Homemade harissa is delicious spread on fresh barley/wheat bread, and there is a variety of other fillings and toppings. One alternative is harissa (homemade or commercial) with a layer of cheese spread and egg omelette, and sliced homemade sun-dried tomatoes and olives. A drizzle of olive oil on top, and it doesn't feel like too much of a betrayal of the tuna!