Juicy green beans and tangy feta cheese pair well with Grilled Butterflied Leg of Lamb.
Cook beans in a large pot of boiling salted water until crisp-tender, 6 to 8 minutes. Drain in a colander; run under cold water to stop cooking.
Whisk oil with vinegar and mustard; season with salt and pepper.
Toss beans with vinaigrette, tomatoes, scallions, and feta.