For Tuna Topping. Chop Shiso leaves. Mix tuna, Shiso, and mayo in a bowl. Put the tuna mixture on Tofu and top with some soy sauce.
For Baby Anchovy Topping. In a frying pan, put sesame oil and anchovies, and cook at medium low heat until crispy. Remove from heat, add thinly sliced green onion and grated ginger. Put the anchovy mixture on Tofu and top with some soy sauce.
For Cucumber and Plum Topping. Slice cucumber very thinly. Sprinkle salt and let sit for 5 minutes. Squeeze out water. Remove the pit from the pickled sour plum and chop its meat to make a paste. Combine cucumber, plum paste, and sesame seeds. Put the cucumber mixture on Tofu and top with some soy sauce.