4 medium beets, scrubbed
1/4 cup balsamic vinegar
1/2 cup water
1/2 cup walnuts, divided
1/4 cup raisins
1 teaspoon Dijon mustard
1 clove garlic
1/4 teaspoon dried thyme
1 1/2 cups cooked chickpeas or 1 (15 ounce) can no-salt or low-sodium chickpeas, drained
5 ounces arugula
