Steam or boil the tuna steaks until fully cooked through, about 15 minutes, then drain and allow them to cool slightly.

Using two forks or your hands, finely shred the cooked tuna meat into small, fibrous pieces, being careful to remove any bones or skin.

Prepare the spice paste by blending the bird's eye chilies, large red chilies, shallots, garlic, and ginger in a food processor until smooth.

Heat the vegetable oil in a large wok or skillet over medium heat.

Add the blended spice paste, bruised lemongrass, galangal, and sliced lime leaves to the pan, sautéing until the mixture is fragrant and the oil begins to separate, about 5 to 7 minutes.

Add the shredded tuna to the pan and stir vigorously to ensure the fish is evenly coated with the aromatic spices.

Reduce the heat to low and continue cooking, stirring constantly to prevent sticking, until the moisture evaporates and the tuna turns golden brown and flossy, approximately 30 to 40 minutes.

Season the mixture with salt and sugar, adjusting the quantities to achieve a balanced savory and spicy flavor.

Remove the pan from the heat and let the Cakalang Abon cool completely before serving over warm rice, porridge, or storing in a jar.