Heat 2 tablespoons of vegetable oil in a large skillet or wok over medium-high heat.
Add the diced onion and bell pepper, sautéing for 3-4 minutes until softened.
Add the minced garlic and cook for an additional 1 minute until fragrant.
Push the vegetables to one side of the skillet. Add the remaining 2 tablespoons of oil and the shrimp to the empty side of the pan. Sprinkle with Cajun seasoning and sauté until the shrimp turn pink, about 2-3 minutes.
Stir in the cooked rice, mixing thoroughly to combine with the shrimp and vegetables. Add the frozen peas.
Create a small well in the center of the rice and crack the eggs into it. Scramble the eggs until fully cooked, then mix them into the rice.
Season with salt and pepper to taste. Cook for an additional 2-3 minutes, stirring frequently to ensure even heating.
Remove from heat, garnish with sliced green onions, and serve with lemon wedges on the side.