In a small, lidded pot, bring rice, 1/4 ts. salt, and 2 cups water to a boil. Reduce heat to a simmer and cook according to package directions. Remove from heat and keep covered.
Meanwhile, heat oil in a large sauté pan over medium heat. Add onion and cook 5 to 7 minutes, until translucent. Add chicken, ginger, garlic, cumin, turmeric (if desired), cayenne, cardamom, and cloves; cook 2 minutes, stirring frequently. Stir in vinegar, scraping bottomm of pan. Add in coconut milk, brown sugar, potato, peanuts, and cinnamon stick; bring to a boil. Reduce heat and simmer, uncovered, 15 to 20 minutes, until potato is cooked. Stir in remaining 1/2 tsp. salt.
Ladle curry over rice. Garnish with chopped cilantro, if desired.