To prepare ravioli, heat 1 tablespoon oil in a skillet over medium-high heat. Add mushrooms, leek, and shallot; cook 3 minutes. Stir in wine and chives. Reduce heat; simmer 7 minutes or until liquid is evaporated. Sprinkle with salt and pepper.
Working with 1 won ton wrapper at a time (cover remaining wrappers with a damp towel to keep them from drying), spoon about 2 teaspoons mushroom mixture into center of each wrapper. Moisten edges of wrapper with water; bring 2 opposite corners together. Press edges together with a fork to seal, forming a triangle. Place ravioli on a large baking sheet sprinkled with cornstarch. Bring 6 cups water to a simmer in a large saucepan; add half of ravioli (cover remaining ravioli with a damp towel to keep them from drying). Cook 5 minutes or until done (do not boil). Remove ravioli with a slotted spoon. Keep warm. Repeat procedure with remaining ravioli.
To prepare sauce, place tomato halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 3 minutes or until blackened; peel. Heat 1 tablespoon oil in a saucepan over medium heat. Add onion and garlic; sauté 2 minutes. Stir in tomatoes, tomato juice, and basil; bring to a simmer. Place tomato mixture in a blender or food processor, and process 1 minute or until smooth. Spoon over ravioli; top with cheese. Garnish with chive sprigs, if desired.