Mix the turkey pieces with turmeric and 1/4 tsp of red chilli powder, and set it aside to marinate for 10-15 minutes.
Heat oil in a large non-stick wok on high heat and stir-fry the turkey for 2-3 minutes till lightly browned. Do not crowd the pan and fry them in batches if necessary. Remove from wok and set aside.
Add in the cumin seeds to the remaining oil in the pan and let it start to sizzle. Now add in the garlic and ginger, and fry for a few seconds till fragrant. Stir in the remaining spices for a few seconds, before adding in the tomato paste.
Mix well to blend in the spices before adding in the onions and the fried turkey pieces. Stir-fry for 2-3 minutes till the onions start to soften. Now add in the peppers and tomatoes, season with salt, and mix well. Let it cook covered for 5-6 minutes till the meat is completely cooked through.
Garnish with fresh cilantro leaves and a squeeze of fresh lemon juice and serve warm.