1. Preheat oven to 400°.
2. Combine first 5 ingredients in a large bowl; stir with a whisk until well blended. Add radicchio; toss gently to coat and allow mixture to seep between leaves. Place radicchio wedges, cut sides down, on a baking sheet coated with cooking spray; drizzle with any remaining vinegar mixture. Place pear wedges, cut sides down, on another baking sheet coated with cooking spray. Roast pears and radicchio at 400° for 12 minutes. Turn radicchio and pears over; roast an additional 12 minutes or until pears are golden and radicchio is browned. Place 2 radicchio wedges and 3 pear wedges on each of 4 plates, and sprinkle evenly with salt. Top radicchio evenly with cheese; serve immediately.