To prepare corn broth, combine 2 1/2 cups water and 2 cups corn kernels in a small saucepan; bring to a boil. Reduce heat, and simmer 5 minutes or until corn is tender. Stir in 1/4 teaspoon salt. Place corn mixture in blender; process until smooth. Strain corn mixture through a sieve into a bowl; discard solids. Set aside; keep warm.
To prepare risotto, bring vegetable broth to a simmer in a medium saucepan (do not boil); keep warm over low heat. Heat butter in a large saucepan over medium-high heat. Add rice; cook 1 minute, stirring constantly. Add onion, carrot, and celery; cook 3 minutes, stirring constantly. Add warm broth, 1/2 cup at a time, stirring constantly until each portion of broth is absorbed before adding the next (about 20 minutes). Add peas, 1 cup corn kernels, fennel, 2 tablespoons cheese, and thyme, stirring until blended and hot. Keep warm.
Combine vinegar, oil, sugar, 1/4 teaspoon salt, and garlic in a small bowl, stirring with a whisk until blended. Place about 1/3 cup corn broth in each of 6 bowls. Top each serving with about 1 1/2 cups risotto; drizzle with 1 teaspoon vinaigrette. Sprinkle each serving with 1 teaspoon cheese, 1/2 teaspoon parsley, and 1/2 teaspoon chives. Serve immediately.