what's the best way to kill cannoneers and dwogres? cannon and just fight like normal with bunyip?

If the defence level in your signature is correct, they'd absolutely rip you apart. I only recommend tanking for 90+ defence as you'd be getting hit for 30's all over the place. You should use proselyte and pray range.

If you use a cannon there you get everyone attacking you. That means range, melee and magic attacks (dworges).

In which case you end up praying range and healing a lot, during the whole time.

 

I find the best way to pray range until they go non aggressive then hit any one in combat for 1+ damage. Since all the non-black guard npc's in that area drop the d pick its worth damaging each of them. In a world with only a few people you can get numerous kills without taking any damage.

Also be aware that if you pray range against the cannoneers, they melee you. The hits are not for much, but there is some damage.

I wear Verac's just cause it has a pray bonus and some defence so I don't get ripped up by the cannoneer's melee. Pray range in the beginning until they're non aggressive, when they aren't aggressive, just let the black guard guys tank for you.