Where can I find dragons for souls?
Just finish Miraak's questline, and you will get your souls back. There are no places where you could farm dragonsouls, without the chance that Miraak will steal them. However, the shouts you need for the questline will be unlocked without needing dragon souls.
Dragons will appear in random encounters throughout the game. You can also look for them in pairs, but they are often in places where you can find other shouts. Other than that, they are in scripted story events.