1. In saucepot, prepare macaroni as label directs, using 1 teaspoon salt in water.
2. Drain macaroni and rinse with cold water; place in large bowl.
3. Cut tomatoes into wedges.
4. If using Kalamata olives, remove pits.
5. Coarsely chop olives.
6. Drain artichoke hearts, reserving 1/4 cup marinade.
7. Stir white wine vinegar into reserved marinade.
8. To bowl with macaroni, add tomatoes, olives, artichokes, marinade mixture, and tuna.
9. Toss gently.
10. Arrange spinach leaves on 4 dinner plates.
11. Spoon pasta salad onto spinach leaves.
12. Top with feta cheese and sprinkle with pepper.