Shrimp, leeks, and pureed potatoes make a savory soup.
Cut leeks in half lengthwise, then into 1/4-inch-thick slices. Place in small bowl, and cover with cold water. Let stand for 5 minutes to rid the leeks of dirt and sand. Lift out of the water, and drain.
In a small stockpot, heat the olive oil and butter over medium-low heat. To the stockpot, add the garlic, leeks, 1/2 teaspoon salt, and 1/8 teaspoon pepper, and saute until the leeks are translucent, about 10 minutes. Add the chicken stock and potatoes, raise the heat to high, and bring to a boil. Reduce the heat to medium, and simmer until the potatoes are fork tender, 12 to 15 minutes. Remove from the heat, transfer soup to a food processor, and puree.
Meanwhile, place the shrimp on a clean work surface and, using a sharp knife, slice each in half lengthwise down the middle of the back, leaving tail on. Remove and discard veins; set shrimp aside.
Transfer the soup back to the stockpot and place over medium heat. Add the skim milk and beans, and bring to a simmer. Raise heat to medium high, add the shrimp, and cook until shrimp are just opaque, about 2 minutes.
Divide the soup among six bowls. Garnish each of the bowls with the diced red peppers and snipped chives, and serve immediately.
This soup can be made in advance up until the point in step four when the shrimp is added.