In a food processor (or by hand though I have done it and it takes a lot longer and a lot more effort) chop brussel sprouts finely.
In a heavy bottom skillet or in the oven, warm the duck legs through. Once warm, separate the skin and reserve, separate fatty bits and discard, pull apart and shred the duck meat. Be sure to reserve the rendered fat from the skillet or pan as well.
Slice bacon into thin strips. Using the same skillet you warmed the duck legs in, cook the bacon until crispy but not very well done. Remove and place on paper towel to drain. Reserve the bacon fat from the pan.
Placing the rendered duck fat from step one and a tablespoon of the bacon fat, bring to medium heat in the same skillet you have been using, and add brussel sprouts to this pan, being sure to coat sprouts in fat. cook over medium-low heat until the nutty flavour of the sprouts outshines their bitterness, approximately 20 minutes, and then turn up heat to medium-high and brown slightly.
Meanwhile, in a separate skillet, render the duck skin you set aside and fry up until a deep golden brown. Remove from pan and slice up into crackling bits.
Toss duck and bacon into browning brussel sprouts just long enough to warm together. Taste and correct for seasoning.