Q:

origin of idiom "small dice"?

I've been using an idiom ambiguously: "That's small dice." 

Does this refer to unfavorable outcomes in games of
chance? (equivalent to "chump
change", like "those are small dice"?). See also "no dice", which has origins in craps. 
Or rather, is the idiom a reference to diced food? (equivalent to "overly scrupulous"?)

Example usage. 

Sorry if this seems like small dice, but I've double booked Wednesday evenings...
Also one time she accidentally tripped me in capture the flag, but that's small dice compared...(weird expression... small dice, what does that even mean?)... [sic] to this one time, we were on a bus going to a music contest for my orchestra, and some of the other people in orchestra dared her to call me "sexy".
http://armorgames.com/community/thread/8027776/the-rant-thread

A:

The idiom I know of is 'small potatoes'.
Perhaps yours is a local adaptation. I get nothing on it, personally, except the NGram (see below).

small potatoes : something or someone insignificant; small fry. This contract is small potatoes, but it keeps us in business till we get into the real money. Small potatoes are better than no potatoes at all.

Free Dictionary.
NGram returns a result for 'small dice' however, falling to 1960, then coming back up to 2000.
NGram for small potatoes shows a stronger result.

