Canned dog food is mainly water, and doesn't give the dog all the nutrients they need. It also *does* cause dental plaque to build up which can cause major issues with a dog's health just as it can in a human. Small dogs have more problems with their teeth to begin with, so feeding them only canned food is asking for trouble, IMO. And unless you brush your dogs teeth every day, be prepared to pay a vet to do several cleanings a year - which isn't good for the dog as they have to be under anesthesia to get their teeth cleaned. My dog get no canned dog food at all. He'll get some boiled chicken once in a while, but I wouldn't give him anything from a can; most have too much garbage in them that I wouldn't put into my dog.
If your dog doesn't like kibble maybe he hasn't had one he likes yet, or you're giving in and giving him too much canned/baby/food etc. when trying to get him to eat dry kibble. If a dog doesn't get anything but kibble for 3 or 4 days he *will* eventually eat it, and he's not going to starve if he doesn't eat for a couple of days. But I have a feeling you might be too softhearted and are giving in by adding things to his dry food before you go a few days with just the dry kibble (mainly because I used to do that with a previous dog myself).
If you try feeding him a good dry food such as Fromm, Solid Gold, Wellness, etc. I wouldn't be surprised if he eats it...not only are these better than any canned food, they're better than most other dry foods...and they're excellent for your dogs health. Also, you can put a few drops of water on the kibble to moisten it, which may get him started eating it...and if he does, then you can phase out putting the water in it.