1. Bring a medium saucepan of water to a boil. Add beans, and cook until bright green and crisp-tender, about 2 minutes. Using a slotted spoon or tongs, transfer to a medium serving bowl. Immediately toss with the salt and 1/2 teaspoon walnut oil. Add walnuts, and transfer to a plate to cool, reserving bowl.

2. Make vinaigrette: In a small bowl, combine shallot with vinegar. Whisk in remaining tablespoon walnut oil until mixture is emulsified.

3. Place salad greens in reserved bowl, and add dressing. Toss well to combine, and season with pepper. Divide among four plates, and pile green beans and walnuts on top. Serve immediately.