To make the glaze, place all the ingredients in a small bowl and stir to dissolve the sugar. Set aside.
Preheat the grill to high and line the grill tray with foil. Cut each slice of prosciutto lengthways into three strips, so you have 12 long strips. Wrap a strip around each prawn, pressing the ham so it stays in position.
Thread the prawns, zucchini slices and cherry tomatoes onto four metal skewers, alternating the ingredients so you start and finish with zucchini slices. Pour half the glaze into a large mixing bowl and reserve for making the dressing. Generously brush some of the remaining glaze over the ingredients on the skewers, then place on the grill tray.
Brush the skewers again with the glaze and grill for 3 minutes. Turn the skewers over and brush with the remaining glaze. Grill for another 3 minutes or until the prawns are pink.
Meanwhile, add the sesame oil and sunflower oil to the reserved glaze and whisk to mix. Add the salad leaves, spinach, spring onions, chives, parsley and coriander. Toss everything together to coat with the dressing.
Divide the salad among four plates. Place a kebab on each plate and remove the skewers, if you like. Sprinkle with the sesame seeds and serve at once, garnished with orange wedges.