1. Bring a large pot of water to a boil. Fill a bowl with ice water. When the water comes to a boil, salt generously and add the greens. Blanch chard for 1 minute, or kale for 2 minutes. Transfer to the ice water, then drain and squeeze out water. Coarsely chop and set aside. Alternatively, steam the greens in a large steamer - 2 minutes for chard, 3 to 4 minutes for kale. Rinse and squeeze dry.
2. In a wide, heavy skillet or Dutch oven, heat the oil over medium heat and add the onion. Cook until the onion is tender and beginning to color, 5 to 8 minutes, and add the garlic, paprika and cayenne. Cook, stirring, for about a minute, until fragrant, and add the tomatoes and salt to taste.
3. Bring to a simmer, and simmer until the tomatoes have cooked down slightly, about 10 minutes. Add the greens, herbs and diluted tomato paste, and bring to a simmer. Cover and simmer until the greens are very tender, about 20 minutes. Add salt and pepper to taste. Serve with rice, bulgur or just some good, crusty bread.
Yield: Serves 4 to 6