Heat ¼ cup olive oil (enough to generously coat bottom of pot) in a large pot on medium to medium-high heat. When hot, add the sausage, breaking it up with a wooden spoon until it starts to brown, about five minutes.
Add the onion, celery, carrots, first two garlic cloves, a pinch of salt, and if you like your soup spicy, a pinch of red pepper flakes. Cook with the sausage until the vegetables soften a bit, another 5 minutes.
Add the lentils, bay leaves, tomatoes, water (6 cups is, conveniently, a little less than 2 empty 28-ounce cans, so you can get any tomato pulp you missed), more salt and black pepper to taste. Bring to a simmer and allow to cook until the lentils are tender, about 40 minutes. (It might be necessary to add more water if the soup gets too thick, though we preferred ours on the thick side.)
When the lentils are cooked, add the chard and cook until the leaves are tender, just a few minutes more. Discard the bay leaves.
To finish, divide soup among bowls, then add the remaining ¼ cup olive oil and 2 garlic cloves to a small skillet (on the stove) and heat over medium until the garlic softens and hisses. Drizzle this over soup bowls, and top with fresh Romano, passing more at the table.