For the salad, saute onion and apples with olive oil and garlic until onions start to soften. Add shrimp and cook while tossing for an additional 2 minutes, or just until shrimp turn pink. Stir in paprika and cayenne pepper. Drain excess liquids and add mixture to the top of the leafy greens. Top with sunflower seeds if desired. Toss with dressing and serve immediately.