Combine 6 cups water and salt in a medium saucepan; bring to a simmer (do not boil). Keep warm over low heat.
Heat 2 teaspoons oil in a large nonstick skillet over medium-high heat. Add squash, bell pepper, and green beans to pan; sauté 6 minutes or until tender. Set aside.
Heat remaining 4 teaspoons oil in a large saucepan over medium heat. Add shallots and garlic to pan; cook 3 minutes, stirring frequently. Add barley; cook 2 minutes, stirring constantly. Stir in wine; cook 2 minutes or until liquid is nearly absorbed, stirring constantly. Add water mixture, 1/2 cup at a time, stirring constantly until each portion of water is absorbed before adding the next (about 45 minutes total). Add squash mixture, and cook 2 minutes, stirring constantly. Remove from heat, and stir in tomato and basil. Top with the goat cheese.