Drain the oil from the canned tuna, but not excessively to avoid dryness.

Wash and dry the perilla leaves, then roll and slice them. Chop the green chilies finely.

Mix the drained tuna with chopped chilies, mayonnaise, wasabi (optional), black pepper, sugar, vinegar, and salt. Stir thoroughly.

If serving children or those who dislike wasabi, omit wasabi and chilies, and add finely chopped onions instead.