In a bowl, combine the cubed chicken with turmeric, chili powder, and salt. Mix well and let it marinate for at least 15-20 minutes.
In a large skillet or wok, heat 2 tablespoons of vegetable oil over medium-high heat until hot.
Add the marinated chicken to the skillet in a single layer. Cook for about 5-7 minutes until browned on all sides, then set aside.
Add the sliced onions, garlic, and julienned ginger to the skillet. Stir-fry for about 3-4 minutes until the onions are translucent.
Add the green and red bell peppers to the skillet and stir-fry for another 3-4 minutes.
Pour in the tomato sauce, smoked paprika, coriander, cumin, and garam masala. Stir well and let simmer for a few minutes.
Return the cooked chicken to the skillet, add the sliced green chillies and water, and stir to combine. Let it simmer for about 10 minutes.
Garnish with fresh cilantro and serve hot with rice or naan.