Green Bean and Radicchio Salad with Roasted Beets and Balsamic Red Onions

Place onion, 1/4 cup vinegar, and bay leaf in large jar or medium bowl. Add just enough water to cover. Season generously with salt and pepper. Cover and chill overnight. (Can be prepared 3 days ahead.) Preheat oven to 350 °F. Place large piece of foil on baking sheet. Place beets in center of foil. Drizzle beets with 1 tablespoon oil and 2 tablespoons water. Top with another piece of foil; crimp edges to seal tightly. Roast beets until tender when pierced with fork, about 1 hour 15 minutes. Cool completely. Cook beans in large pot of boiling salted water until crisp-tender, about 6 minutes. Rinse under cold water to cool. Drain and pat dry. Whisk remaining 6 tablespoons balsamic vinegar, 1/2 cup oil, shallots, and thyme in small bowl to blend. Season dressing with salt and pepper. (Beets, beans, and dressing can be made 1 day ahead. Cover separately and refrigerate.) Peel and cut beets into 1/4-inch-thick slices. Arrange large radicchio leaves over very large platter to cover (reserve small leaves for another use). Drain red onions; scatter over radicchio. Arrange beans over onions. Arrange beet slices decoratively over beans. Pour dressing over salad and serve.