1/4 cup walnuts
4 miniature assorted color beets, (about 1 1/2 pounds), with beet stems trimmed to 1/2-inch
1 1/2 tablespoons Sherry vinegar
3 tablespoons extra-virgin olive oil
1 tablespoon finely chopped fresh flat-leafed parsley leaves
Freshly ground black pepper
2 bunches arugula, trimmed and washed, for salad bed