Heat oven to 400°. In a small bowl, stir together blue cheese, yogurt and milk; set aside.
Toss potatoes with 1 tablespoon of the oil and ½ teaspoon of the thyme; place potatoes in a rimmed baking sheet and bake at 400° for 5 minutes.
Sprinkle pork with remaining ½ teaspoon thyme, ½ teaspoon of the salt and the pepper. Heat remaining 1 tablespoon olive oil in a large nonstick skillet over medium-high heat. Add pork to skillet and cook for 8 minutes, flipping halfway through, or until browned. Remove pork from skillet and nestle in center of potatoes, pushing them to either side; set skillet aside. Return pork and potatoes to oven and roast an additional 25 minutes or until internal temperature of pork registers 155° on an instant read thermometer.
Return skillet to medium-high heat and heat remaining 1 tablespoon oil. Add green beans and onion to pan and sprinkle with remaining ½ teaspoon salt; cook, stirring often, for 3 minutes. Add radicchio and cook for 5 more minutes, stirring often; remove from heat and set aside.
Remove pork and potatoes from oven; stir potatoes into skillet and drizzle with half of prepared dressing. Cut pork into 1/2-inch slices. Transfer contents of skillet to a serving platter and top with pork slices; serve with remaining sauce immediately.