In a small skillet, cook pancetta over medium heat until crisp, stirring occasionally. Remove with a slotted spoon; drain on paper towels.
In same pan, heat oil and drippings over medium heat. Add onion; cook and stir 1-2 minutes or until tender. Add tomatoes, rosemary, salt and pepper; cook 2-3 minutes longer or until tomatoes are softened. Cool slightly.
In a large bowl, combine beans, tomato mixture, pancetta, vinegar and basil. Add arugula and cheese; toss to coat.
