Combine 2 cups water with 1 cup rice grits, a pat of butter and 1 teaspoon of salt. Bring to a boil. Stir once. Cover and simmer on low for about 20 minutes, or until water has been absorbed and rice grits are tender. Keep covered; remove from heat and let sit for 10 minutes.
While grits cook, heat oil in a large skillet over medium-high flame. Cook onions and garlic until onions are translucent. Add shrimp and sauté, tossing occasionally, until shrimp turns pink, about 3 minutes. Season with paprika, sea salt and pepper. Stir cheese into grits, if using. Season with salt and pepper and divide between two plates. Top with shrimp.