Cook the pasta according to packet instructions (usually for 9-12 minutes in a pan of boiling salted water). Drain, rinse under cold water and transfer to a large mixing bowl.
While the pasta cooks, place the ingredients for the dressing in a blender and blitz to a smooth dressing.
Mix together the pasta, tomatoes, cucumber, onions and olives.
Place the salad leaves on 2 plates, divide the pasta mix between them, and crumble on the feta.
Drizzle over the yoghurt dressing and serve.