Is rare duck breast safe? Other forms of poultry are regarded as undercooked at the slightest sign of pink juices and yet it is common practice to cook duck so that it's medium rare. Is the risk of food poisoning significantly lower with duck meat than other birds?

On the other hand, if we could be sure that a piece of chicken could was salmonella-free, would its texture and flavor be improved by not overcooking it? I expect the sight of pink would put most people off but if one could overcome that, could it actually taste better?
Rare duck meat is safe to eat because it does NOT contain the same risk of Salmonella as does chicken meat.

Primarily because ducks, as mentioned above, have not traditionally been raised in the same squalid conditions as "factory raised" chickens - salmonella is a disease that is primarily transmitted through dirt/dirty unclean conditions. 

Now, on the other hand, as more and more ducks are being raised in industrial conditions, they are also becoming more likely to contain strains of Salmonella.