In a small pot, place the potato and boil until soft. Drain and mash. Reserve for later use.

Place onion and celery in a small saute pan and saute for 7 minutes until just turning brown.

Put them in a large bowl, add tuna, egg whites, salt, pepper, scallion, carrot and matzo meal or flour. Add mashed potato and combine by hand until well mixed.

Heat a non-stick saute pan and spray with some cooking spray.

Make small balls out of this mixture by hand and lay them on the skillet to brown. Flatten slightly with a fork, taking care not to break them.

Fry on both sides until browned and slightly crispy. Serve immediately.