Bring green beans and water to a boil in a large skillet. Reduce heat to a simmer, cover and cook until the beans are just tender, 3 minutes. Uncover and continue cooking, stirring occasionally, until the water has evaporated, 3 to 4 minutes more.
Add oil, salt and pepper to the pan and cook, stirring, 1 minute more. Transfer the beans to a large bowl and toss with blue cheese until well coated. Sprinkle each serving with walnuts.
Tip: To toast chopped or sliced nuts, stir constantly in a small dry skillet over medium-low heat until fragrant and lightly browned, 2 to 4 minutes.
1 vegetable, 1/2 high-fat meat, 2 fat