Preheat oven to 425°.
Leave root and 1 inch of stem on beets; scrub with a brush. Place beets in a small baking dish. Bake at 425° for 50 minutes or until tender. Cool. Trim off beet roots; rub off skins. Dice beets.
Combine beets, pear, celery, and pistachios in a medium bowl.
Combine juice and next 5 ingredients (juice through red pepper), stirring well with a whisk. Drizzle over beet mixture, tossing gently to coat.
Serve at room temperature or chilled on lettuce leaves, if desired.