In a small bowl, combine sambal oelek, tomato ketchup, light soy sauce, rice vinegar, and sugar. Mix well and set aside.
Heat oil in a wok or heavy-bottomed pot on medium-high heat, add cashew nuts, saute until golden brown and set aside.
Next, add minced ginger-garlic and broken dried red chiles, sauté until ginger-garlic are fragrant.
Add sliced onion, red and green bell peppers, sauté for 2 to 3 minutes.
Add salt and pepper to season the veggies.
Add in the sauce mixture. Mix well, cook for 1-2 minutes or until it begins to bubble.
Now add the cornflour slurry. Give the slurry a good stir before pouring and continue mixing until it thickens up.