Can we find some statistics for crime in Japan with tourist / foreign victims?

The Japanese Police Agency only lists crimes committed by foreigners (and does have them listed by both country of origin of the offender, and part of Japan they were committed in).

The Wikipedia Article focuses again on crimes committed by foreigners, rather than crimes against foreigners.

The best that I can find is the US government site on visiting Japan:

The general crime rate is below the U.S. national average. Crimes against U.S. citizens usually involve personal disputes, theft, or vandalism. Pickpocketing and other petty crimes do occasionally take place in crowded shopping areas, bars/nightclubs, train stations, and airports. Every year, a number of U.S. citizens report their passports lost or stolen at Narita airport.

Other high-risk areas for crime include Shinjuku, especially the areas of Kabuki-cho, Shibuya, and Ikebukuro. However, all personnel should use caution in all entertainment and nightlife districts throughout Japan. Incidents involving U.S. citizens since the spring of 2008 in these areas include physical and sexual assaults, drug overdoses, thefts of purses, wallets, cash, and credit cards at bars or clubs and drugs slipped into drinks.

^{(No, these are not stats)}

There are very few foreigners in Japan (especially if you separate out those with special permanent residence). The crime rate is also incredibly low (for instance, there were 1,031 thefts reported across the country from the months of January to April 2014). In a year you'd likely not get a single incident reported in a every prefecture.

I would bet that due to the incredibly small sampling size, if the government doesn't record them, there isn't much a chance of getting an objective estimate from a third party. I tried to find something, but (understandably) the Japanese are more concerned about crime by foreigners, or crime against tourists/immigrants from Japan in places overseas.