Have you tried just adding water to the kibble, stir it up to make gravy, and let set for about 10 minutes; then feed? You say both dogs. Does the other dog eat this with no problem? You might just have a really finicky dog and only likes topped with canned food. A lot of people top their food to feed their dogs. A lot will say just set bowl down for 10 - 15 minutes and if he don't eat it remove food till next feeding "if he is hungry he will eat" I have tried this method myself and like you I didn't want my dog getting sick. "maybe try feeding at different times. Early in the morning, a little bit at lunch, then late in the evening. You will have to see what clicks with the problem dog.
"A House Is Not A Home Without A German Shepherd"