In 4-quart Dutch oven cook garlic in oil for 15 seconds; add leeks. Cook and stir until tender. Add broth, water, beans, and thyme; bring to boiling. Add linguini. Simmer, uncovered, for 10 to 12 minutes or until pasta is just tender, stirring occasionally. Stir in seafood. Simmer 2 minutes or until seafood is just opaque. Divide among soup plates. Add tomatoes and arugula. Season to taste with pepper. Makes 4 servings.