How to Make It
Heat oil in a large nonstick skillet over medium-high heat. Add onion, ginger, and garlic to pan; cook 6 to 7 minutes or until starting to brown, stirring occasionally. Stir in tomato paste and tomatoes; bring to a simmer, and cook 3 minutes. Combine 1/3 cup water and flour in a small bowl, stirring with a whisk until smooth. Add flour mixture, garam masala, paprika, curry powder, salt, and pepper to pan; stir well. Bring to a boil; cook 1 minute.
Place chicken thighs in a 6-quart slow cooker coated with cooking spray. Add tomato mixture to slow cooker. Cover and cook on LOW 7 hours or until chicken is very tender and sauce has thickened. Turn slow cooker to HIGH; uncover and add coconut milk, stirring with a whisk. Cook, uncovered, 15 minutes. Turn cooker off; stir in cilantro. Let stand 10 minutes. Serve over rice. Top each serving with 1 tablespoon yogurt.