1 teaspoon fresh lemon juice
1 teaspoon finely chopped fresh flat-leafed parsley leaves (wash and dry before chopping)
1/2 teaspoon freshly grated lemon zest
freshly ground black pepper to taste
Trim stems off beans and cook in boiling salted water until crisp-tender (2 minutes for haricots verts, thin, French bean, or 3 to 4 minutes for regular yellow wax or green beans). Drain.
Move to a bowl and toss beans with lemon juice, parsley, lemon zest, and pepper and season with salt.