The Romaniote Jews of Greece always maintained a special relationship with the holiday of Passover. As a result they took on the names that are associated with the holiday, as both personal names and surnames. Names like Pessah, Matza (a famous Greek-Jewish family in Israel), and Hametz (I had the privilege of meeting a young Romaniote Rabbinical student with this surname, Tzvi Hametz, last year). Tzvi also mentioned to me that he knew of a Greek-Jewish family who took on the amusing surname of 'kol hamira'. This Aramaic prayer כל חמירא וחמיעא is recited during the evening preceding the 14th of Nissan, and renders all the left-over unleavened bread in one's property null and void. It also recited by many on the day of the 14th, while burning the left-over hametz. The formula and translation follows (courtesy of Jewish in St. Louis) :
Kol chamira va-chami’ha d’ika vir’shuti, d’la chamitei u’d’la viartei u’d’la yadana lei livteil v’lehevei hefker k’afrah d’ar’ah.
All manner of leaven which is in my possession, that I have not seen or removed, shall be annulled and considered as the dust of the earth.
Kol chamira va-chami’a d’ika virshuti, da-chazitei u’d’la chazitei d’chamitei u’d’la chamitei, d’viartei u’d’la viartei livteil v’lehevei hefker k’afra d’ar’ah.
All chametz in my possession, whether I have seen it or not, whether I have removed it or not, is hereby nullified and owner-less, as the dust of the earth.
A little online searching brought me to a webpage that was created by a member of this mentioned family (spelled there 'colchamiro').
According to one version of the family story, this is how the name came into being:
The story we always tell is that our ancestor was a rag merchant in Greece and was very meticulous about picking good scraps; that he would look through the goods as carefully as one looks for leaven on Passover. The prayer that one says after locating all leaven in the house is called "Kal Chamira" and so his friends and associates said he was so picky that he might as well say "Kal Chamira" over his rag finds. Supposedly he was known by this name in Greece and gave it when arriving at Ellis Island, and that the immigration officials invented their own spelling.See more about this remarkable family here
Professor Rae Dalven who wrote a book on the Ioannina Romaniotes entitled The Jews of Ioannina, writes:
"My mother's maiden name was Kalchamira (spelled Colchamiro in the United States). The family explanation is that her father, a cloth merchant, used to examine material as closely as if he were searching for leaven (hametz). This was associated with the statement made the night before the eve of Passover, beginning KAL HAMIRA DE IKA BIRSHT (May all leaven in my possession)."
By a stroke of incredible coincidence, an Israeli journalist researched this very same same topic, at the same time as I did. His article appears here (in Hebrew).