Crimp and fold the edges of a double layer of aluminum foil so it resembles a rimmed baking sheet. Put the beans in the center and toss with 1 tablespoon of the oil, 1/4 teaspoon salt and 1/4 teaspoon pepper. Add 2 tablespoons water.
Place the foil on the grill cook, tossing the beans occasionally, until lightly charred and tender, about 15 minutes.
While the beans grill, cook the bacon in a small skillet over medium heat until crisp; transfer to a paper-towel-lined plate to drain. Pour off all but 1 tablespoon of bacon drippings and then stir the mustard, vinegar and remaining 1 tablespoon oil into the skillet until combined.
Transfer the beans to a servings bowl and pour the warm vinaigrette over top. Toss well, scatter with the cooked bacon and adjust the seasoning with additional salt and pepper.
Copyright 2016 Television Food Network, G.P. All rights reserved.