Cook bacon in a large skillet set over medium-high heat until crisp. Use a slotted spoon to remove bacon pieces and drain them on a paper towel-lined plate. Pour off excess grease from the skillet, leaving about 2 tablespoons in the pan.

Add the garlic and red pepper flakes to the bacon grease and cook over medium-high heat until fragrant, about 1 minute. Add green beans and season with salt and pepper. Cook and stir until beans are tender but still a little crunchy, about 10 minutes. Return bacon to the pan and toss with the beans before serving.