Bring 1 cup of water to a boil in a small saucepan over medium-high heat.
Slowly whisk in the stone-ground grits and the sea salt, then reduce heat to low and cover.
Simmer the grits for 15 to 20 minutes, stirring occasionally, until the texture is tender and the liquid is absorbed.
While the grits cook, heat the olive oil in a non-stick skillet over medium heat.
Add the diced yellow onion and red bell pepper to the skillet, sautéing for 4 minutes until the vegetables are translucent.
Season the shrimp with Cajun seasoning and black pepper, then add them to the skillet with the vegetables.
Sauté the shrimp for 2 to 3 minutes per side until they are pink, curled, and fully cooked through.
Remove the grits from the heat and vigorously stir in the Greek yogurt to create a velvety, rich consistency.
Portion the creamy grits into a bowl and top with the spicy Cajun shrimp and sautéed vegetables.
Garnish the dish with fresh sliced green onions before serving.