Preheat oven to 160'C .Place the mozzarella apart on trays lined with baking paper .Bake for about 5 minutes, or till melted .Remove from the oven.
1
Mix the tuna , mayonnaise an onion . Divide the tuna between the centres of the cheese squares .Then fold over the filling to enclose making triangles . Firmly press the sides together to enclose.
2
Sprinkle with sesame seeds and bake for about 20 minutes, or until the edges are golden brown.Serve hot or at room temperature.