In a large skillet, heat the vegetable oil over medium heat. Add the chopped onion and sauté until translucent, about 3-4 minutes.
Stir in the minced garlic and ginger, cooking for an additional 1-2 minutes until fragrant.
Add the sliced red and green bell peppers to the skillet and cook for another 3-4 minutes until they begin to soften.
Pour in the coconut milk and stir in the curry powder, fish sauce, soy sauce, and sugar. Bring the mixture to a gentle simmer.
Add the shrimp to the skillet and cook for 5-7 minutes, or until the shrimp are pink and cooked through. Season with salt and pepper to taste.
Remove from heat and garnish with fresh cilantro before serving.