I suppose you're referring to the phrase "Fukui-san", which is a polite way of addressing Kenji Fukui:
He's saying "Fukui-san." Because the guy who's attention he's getting is Fukui Kenji.
This is even mentioned on Shinichiro Ohta's Wikipedia page:
Ohta's character is perhaps best known for his line, "Fukui-san?" (Mr. Fukui), which he would say several times per episode, when interrupting Kenji Fukui's commentary with a report from the field.
As explained on Wikipedia, "San" is a honorific:
San, derived from sama (see below), is the most commonplace honorific and is a title of respect typically used between equals of any age. Although the closest analog in English are the honorifics "Mr.", "Miss", "Ms.", or "Mrs.", -san is almost universally added to a person's name; "-san" can be used in formal and informal contexts and for any gender. Because it is the most common honorific, it is also the most often used to convert common nouns into proper ones, as seen below.
Kenji Fukui is of course:
the "play by play" announcer of Iron Chef