This worked well for me with buffleheads. Probably one of the worst tasting ducks.
1.5-2lb diver breasts, soaked and blood removed as much as possible
Green bell pepper chopped
Half a medium size white onion onion chopped
2-3 garlic cloves chopped
2-3 TBSP of apple cider vinegar
1/2 can of chunked pineapple
1 bottle of regular BBQ sauce (tried with Hawaiian style and I didn't like it), less if you want a less liquid BBQ style
1) Mix everything but the diver breasts together in a large bowl
2) Place half the breasts flat in a crock pot. Place half the sauce mix on top. Repeat on top of that with breasts/sauce
3) Set on low for 6 hours
4) After 6 hours pull breasts apart with two forks, creating a pulled BBQ of sorts
5) Let it sit on "warm" for another 4-5 hours
Serve on toasted buns with fresh coleslaw.