Cut red bell pepper in half lengthwise; discard seeds and membranes. Place red and yellow pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 15 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 10 minutes. Peel and dice; place in a large bowl.
Cook pasta according to package directions, omitting salt and fat. Add haricots verts to pasta during last 3 minutes of cooking time. Drain. Add pasta mixture, tomatoes, and next 4 ingredients (through prosciutto) to peppers; toss well.
Heat a small saucepan over medium-low heat. Coat pan with cooking spray. Add garlic and shallot to pan. Cook 15 minutes or until soft, stirring occasionally. Place the garlic mixture, vinegar, and remaining ingredients in a blender; process until smooth. Pour dressing over pasta mixture; toss well.