Preheat oven to 475 degrees. In a small bowl, combine yogurt, cilantro, lemon juice, and garlic. Season with salt and pepper; set sauce aside. Cook rice according to package instructions; set aside.
Break cauliflower into large florets; place on a rimmed baking sheet with onions. Sprinkle with oil and curry powder. Season with salt and pepper; toss to coat. Roast, tossing occasionally, until tender and browned in spots, 25 to 30 minutes.
Heat a large skillet over medium-high heat; sprinkle 1 teaspoon salt evenly in the bottom of skillet. Add 4 chops, and cook on both sides, 2 to 4 minutes per side for medium-rare. Transfer to plate. Wipe skillet with paper towel; repeat with remaining chops. Serve lamb with rice, cauliflower, and yogurt sauce.