Cut tomatoes, peppers, and onion into chunks. Set aside ¼ onion and add remaining produce to a blender with about ¼ cup of water. Blend until liquefied then set aside.
Meanwhile, add enough oil to a large pot or skillet to coat the bottom of the pot over medium-high heat. Slice the remaining onion into thin strips and add it to pot, followed by chicken, black pepper, and sea salt. Cook for about 10 minutes or until chicken begins to brown and release juices.
Pour tomato mixture into pot, followed by tomato paste and sauce. Add crushed maggi cubes, curry powder, and white pepper and stir until incorporated.
Let stew cook, stirring regularly and reduce heat to medium if it begins to splatter too much. After 10 minutes or so, the tomato mixture should become bubbly, thickened, and darker in color. Continue stirring to release more of the liquid. The oil that cooked the chicken will cook the raw tomato taste out of the stew.
Next, taste test and salt the stew as necessary. The maggi has a lot of salt so you may not need to add much. Continue cooking until the stew reaches your desired consistency and some of the oil dissipates. If desired, spoon out any excess oil upon completion.
Serve with cooked rice or starch of your choosing.