In a large bowl, mix together 1 tablespoon olive oil, chili flakes, lemon zest, 1 tablespoon garlic, thyme and shrimp. Season with salt and pepper and allow to marinate in the refrigerator for at least 20 minutes.
Heat a grill pan to medium high and cover lightly with cooking spray. Grill shrimp until they turn pink -- about 1-2 minutes on each side. Remove from pan and tent with a piece of foil.
Meanwhile, heat the shrimp stock in a medium saucepan and keep warm over low heat.
Heat the remaining olive oil in a large skillet over medium heat. Add onion and remaining garlic to the skillet. Cook until items are translucent -- about 5 minutes. Add the rice and stir quickly until it is well-coated and opaque. Stir in wine and cook until the liquid is nearly all evaporated.
Ladle in 1 cup of broth into the rice. Simmer and slowly stir until the rice has absorbed the liquid. Add the remaining broth, 1 cup at a time. Continue to simmer and stir, allowing the rice to absorb each addition of broth before adding more. The risotto should be slightly firm and creamy –approximately 20 minutes total.
Gently fold the grilled shrimp into the risotto. Stir in Parmigiano-Reggiano cheese and cook briefly until the cheese has melted. Check for seasonings and adjust with salt and pepper if needed. Spoon risotto into dishes and top with chopped parsley before serving.
*The shrimp stock is a key component in layering the shrimp flavor throughout the entire dish. It can be made by simmering 2½ quarts of water with shrimp shells, 1 onion roughly chopped, 2 carrots roughly chopped, 2 cups celery roughly chopped, 1 teaspoon black peppercorns, 2 bay leaves, and a generous amount of sea salt. Simmer for 30 minutes, strain and use accordingly.