In a medium saucepan, bring water to a boil. Add salt, then grits and cook, stirring frequently, until thick, about 10 minutes. Stir in cheese. Keep warm.
In a large saucepan, heat olive oil over medium high heat until shimmering. Season shrimp with salt and pepper, add to pan, and saute until cooked through, about 1 minute per side. Remove shrimp with a slotted spoon and set aside.
Whisk flour into pan and cook, stirring constantly, until pale golden, about 1 minute. Whisk in chicken broth, garlic, scallions, salt, pepper, and hot sauce. Cook until slightly reduced, about 3 minutes. Add shrimp and spinach to pan and cook until spinach is wilted.
Place grits on every plate and top with shrimp, spinach, and sauce.