1. Combine 1/2 tablespoon garam masala, 1/2 tablespoon curcuma/turmeric, 1 teaspoon salt, cumin, coriander, and pepper in a 1 gallon zip-lock bag. Add the chicken cubes, mayonnaise and lemon juice to the bag, seal and massage to coat. Refrigerate the bag for 30 minutes (up to 3 hours).
2. Preheat the oven to 400 degrees F.
3. Line a baking sheet with parchment paper, evenly spread the chicken on baking sheet. Bake the chicken for 5-6 minutes on each side.
4. In the meantime, heat oil and sauté onions until translucent. Add garlic, ginger, chiles and remaining dry spices. Add tomato sauce and simmer for about 15 minutes until onions are soft. Add baked chicken and coconut milk. Mix well, making sure the chicken is evenly coated with the sauces and heat through.
5. Serve over basmati rice or Israeli couscous (discard chile peppers before serving).