actually no kibble should be soaked for long periods of time, it's better to just add water and serve, otherwise there's always the issue of bacteria overgrowth or the soaked kibble turning sour.
there is nothing wrong with soaking kibble for a few minutes tho, for example for puppies or dogs who have problems eating hard food for some other reason.
microwaving food isn't a good idea since there is the danger of certain parts of the food portion becoming overheated and burning the mouth or tongue, and besides that it destroys nutrients.