To make the chutney: Combine sugar, vinegar, ginger, garlic, cumin, cinnamon, and cloves in a large saucepan. Bring to simmer over low heat, stirring occasionally, until sugar dissolves. Add rhubarb, onion and raisins. Increase heat to medium-high and cook until rhubarb is tender and mixture thickens slightly. Remove from heat and let cool completely.
Preheat oven to 400 degrees F (200 degrees C).
To cook pork: Sprinkle pork with cumin, salt and pepper. Heat oil in large, heavy skillet over high heat. Add pork and brown on all sides, about 5 minutes.
Transfer pork to roasting pan. Brush with 6 tablespoons of the chutney that has been pureed. Place in preheated oven, brushing occasionally with 6 more tablespoons chutney. Cook until thermometer inserted into center registers 155 degrees, about 25 minutes. Slice pork into medallions. Garnish with cilantro sprigs and serve with remaining chutney.