Preheat oven to 400 degrees F. Trim root end off of beets so that raw skin is exposed, and also trim tail end. Rub with olive oil. Wrap in foil and place in baking dish. Bake for 1 hour or until beets are tender.
Let beets cool, and drain beet juice into small bowl. When cool, run under cool water and peel. Then cut beets into small cubes.
Meanwhile, rinse rice in a colander, until white runs clear. Add to pot and cover with 1 1/2 cups water, 1 teaspoon oil, and 1 teaspoon salt. Bring to boil. Reduce heat to low-simmer and cover with a lid. Cook for 15 minutes. Remove from heat, keeping lid on, and let sit for 10 minutes. Fluff with fork.
To make salad, combine rice, beets, cabbage, walnuts, parsley, and lemon juice in a bowl. In the small bowl with beet juice, add sour cream, red wine vinegar, garlic, mustard, and remaining salt. Whisk to combine, then add to salad bowl. Stir together to coat. Serve room temperature or cold.