Heat the oil in a large skillet over medium-high heat. Add the curry powder and cook, stirring frequently, for 5 to 6 minutes. Add the sliced onion and continue to cook, stirring occasionally, until the onion is translucent, 4 to 5 minutes. Add the garlic, salt, pepper and paprika and cook for 1 more minute.
Add the chicken and stir to coat it with the mixture. Add the stewed tomatoes, coconut milk, brown sugar and ginger. Stir to combine and bring to a simmer. Cook, uncovered, for about 40 minutes, stirring occasionally, until the curry has thickened as much as you would like. Stir in the lime juice, coconut and cashews.
Serve the curry over cooked rice. Garnish with green onions and/or cilantro and additional coconut and cashews, if desired.