Cut papaya in half and remove seeds. Reserve 2 tablespoons of seeds for the dressing. Peel and dice the papaya, and place in a medium bowl. Add tomatoes, red onion, red pepper and basil, and set aside.

In a food processor or blender, combine the papaya seeds, sugar, wine vinegar, oil, mustard and green onions. Process until smooth and thick, and most of the seeds have broken up. Pour over the papaya mixture and stir to coat all of the ingredients.