A bidet can be used in micro-gravity, if you isolate the lower torso with a velcro-fitted cover and employ a vacuum hose to recover spent water.
However, this is rather inefficient in terms of water and electricity consumption. All of the water would be considered wastewater/"grey" water and will have to go through a series of filters and tanks/canisters. Considering the (substantial) burden of managing toilets aboard the ISS, this would reduce crew time available for science. Wet wipes are more cost-effective right now.
In terms of engineering required, a functioning bidet will be akin to a working shower. A shower, a bidet, re-usable washable garments and more comfortable ways of urinating and taking a dump are the basic elements of ECLSS of the future, where humans won't have to endure space travel but to live and relish it.