Rinse the chicken and pat dry with paper towels. Sprinkle with salt.
Coat the bottom of a 5 to 7 quart dutch oven with a thin film of the oil and set over medium heat. When oil simmers, add chicken, skin side down, without crowding; do it in bathes if necessary. Cook until skin is golden brown and releases easily from pot when lifted with tongs, about 5 minutes. Turn pieces over and cook until they brown and release easily on the other side, about 5 minutes more. Transfer browned chicken to plate.
When last batch of chicken has been removed, add the onion, garlic and ginger to pot and cook stirring until vegetables are soft and fragrant, about 3 minutes. Add the curry powder, cumin, cayenne and 1/2 tsp salt. Cook for 30 seconds until spices are fragrant, then stir in the tomatoes and 1 cup of the coconut milk.
Stir well and let come to a boil. Return the chicken and any accumulated juices to the pot; chicken should be surrounded by sauce but not submerged into it, so that the top most skin is exposed (if by any chance there is not enough liquid add remaining coconut milk) Reduce the heat ans simmer, uncovered until chicken is opaque at the bone, about 45 minutes. Stir in the peas and cilantro and cook until peas are hot about 5 minutes more.