Toss the green beans into a large pot of boiling salted water and cook until bright green in color and crisp-tender, about 5 minutes. Drain the beans and shock in a large bowl of ice water to stop the cooking. Drain the beans again and pat dry.
Cook the bacon in a large, heavy saute pan until crisp, about 5 minutes. Remove the bacon to a paper towel-lined plate to drain. Spoon off the excess bacon grease, leaving 2 tablespoons in the pan. Add the onion to the pan and saute until soft and very tender, 4 to 5 minutes. Sprinkle in the garlic and red pepper flakes and saute until just fragrant, about 1 more minute. Add the reserved green beans and the pecans and cook until heated through, 5 to 6 minutes more. Return the bacon to the pan, pour in the lemon juice and toss. Season with salt and pepper.
Photograph by David Malosh
Recipe courtesy Pat Neely for Food Network Magazine