Hey, mass murder can be a very good strategy for certain provinces.
Keep in mind that a province's growth rate is affected by religious tolerance- having it be a religion you love (say, your state religion) can be worth 5% more in growth than a religion you just tolerate (middle of the bar). That means that for medium (20,000 or less) provinces, the increase in growth is enough that in 40 or 50 years you'll be caught up from knocking them down to 5000- and by caught up, I mean at the point you would have been had you let it grow normally. And *from* that point, it'll grow faster and have less risk of revolting, which is a big benny.
So unless it's a *huge* province, give them a tax collector and set your religious tolerance to 0, then sit back and let them revolt. Don't bother attacking a revolt until they've taken the city, then drop in and seige. You can keep checking up on their population by right-clicking on the province and selecting "View".
Of course, keep in mind that by setting that religious tolerance to the minimum, you're telling all countries that have that as a state religion to go sod off- so be carefull on that one.