Add the tuna to a food processor and pulse to grind. Transfer to a bowl and stir in the chives, tamari, garlic and black pepper to taste. Form the tuna mixture into 8 small patties. Place the panko and sesame seeds in a shallow dish. Coat the patties in the panko mixture.
In a large skillet, heat the oil over medium-high heat. Add the patties and cook until lightly golden-brown on the outside and pink in the middle, about 2 minutes per side.
Slather the roll tops with the wasabi mustard (or sweet-hot mustard). Place the burgers on the roll bottoms. Top with the lettuce, pickled ginger and roll tops. Serve with the root-vegetable chips.