Drain any liquid from the tuna. Put 5 to 6 ounces of tuna in the soup bowl.
Put 2 tablespoons of mayonaisse and mix well with the tuna, breaking up and shredding any clumps of tuna.
Lay two slices of bread on a plate. Put two small scoops of the tuna mixture on one of the slices. Spread and level out the tuna mixture evenly until that slice is almost completely covered.