Drain the 2 cans of tuna flakes in a strainer and press the tuna against the strainer using a spoon to remove excess liquid.
Heat a non-stick pan and put about 1 tsp of cooking oil. Stir fry the tuna until the liquid is almost gone and the tuna turns almost brown.
Put more oil in the pan about 1 Tbsp and fry the tuna until crispy and brown. Then set aside in the pan forming a circle.
Add in the center 1 tsp of oil and add in ginger, onions, green chili peppers, siling labuyo and bell peppers. Saute for about half a minute then mix the tuna with the spices.
Then season with liquid seasoning, soy sauce, calamansi juice, sugar, black pepper and stir all the ingredients. Turn off heat.
Add in the mayonnaise and stir to mix. Put the crushed chicharon and stir again to mix.
Heat the sizzling plate and melt the butter and spread it on the entire plate. Put the tuna sisig on the plate and give it a little toss.
Serve hot and garnish with crushed chicharon and slices of calamansi.