1. Combine first 5 ingredients in a small cast-iron pan over medium heat; cook 5 minutes until toasted and just beginning to smoke, stirring occasionally. Remove from heat. Place spice mixture and chili powder in a spice or coffee grinder; process until finely ground.
2. Return pan to medium heat. Add 1 tablespoon oil; swirl to coat. Add onion; cook 4 minutes or until tender, stirring occasionally. Add garlic; cook 2 minutes, stirring frequently. Remove from heat; cool completely.
3. Combine spice mixture, onion mixture, breadcrumbs, 1/2 teaspoon salt, lamb, and egg in a large bowl. Shape mixture into 12 meatballs. Heat a large nonstick skillet over medium-high heat. Add remaining 1 tablespoon oil to pan; swirl to coat. Add meatballs; cook 6 minutes, browning on all sides. Remove meatballs from pan; drain well. Wipe drippings from pan with a paper towel. Return meatballs to pan. Add kale, stock, and remaining 1/4 teaspoon salt; bring to a boil. Reduce heat, cover, and simmer 4 minutes. Remove from heat; let stand, covered, for 5 minutes.
4. Combine yogurt, lemon juice, and ground cumin in a small bowl. Spread 2 tablespoons yogurt mixture in bottom of each of 4 shallow bowls. Top with 1/2 cup rice and 1 cup lamb mixture. Sprinkle evenly with pine nuts and mint.