The metal the tanks are made of is thicker than the stuff used in cars. I had a paintless guy try for about 3 hours to get a small dent out of a tank and to no avail couldnt do it. Filler or having it popped out by some other bodywork means is your answer.
It is my understanding that he pops the dent and primes the tank. If you need it painted, I can ask around to see who the preferred bike body work painter is. CT at Primo jus got a tail section painted so he would be a good person to ask.