2 firm nectarines, halved and cut into thin slices
2 medium red bell peppers, seeded and halved
4 very thin slices red onion
1/2 cup fresh orange juice
Juice of 1 lime
1/8 tsp. ground turmeric
2 tsp. extra virgin olive oil
Salt and freshly ground black pepper
1 tsp. fresh oregano, minced
Place shrimp in a large saucepan filled with cold water. Bring to a boil over medium-high heat. When shrimp have turned pink and curled, drain and peel them. Remove their veins. Halve each shrimp lengthwise and set aside.
Arrange a quarter of the spinach in a bed on each of 4 dinner plates. (If using flat-leaf spinach, first tear it into bite-size pieces.) Arrange 4 nectarine slices on each bed of spinach. Cut pepper halves into strips. Cut strips into thirds. Arrange one-fourth on top of nectarine slices. Arrange one-fourth of the shrimp over the peppers. Separate onions into rings and arrange over shrimp.
For the dressing, whisk orange and lime juices in a small bowl with turmeric and oregano. Whisk in oil.
Season to taste with salt and pepper. Spoon 2 tablespoons dressing over each salad. Sprinkle oregano on top and serve. (Salad can be assembled and dressing made up to 4 hours ahead. Cover with plastic wrap and refrigerate. Dress and garnish just before serving.)