Cook pasta according to package directions, omitting salt and fat. Drain and set aside.
Wash peas; trim ends, and remove strings. Cook, uncovered, in a small amount of boiling water 3 minutes. Drain; set aside.
Coat a large skillet with cooking spray; place over medium-high heat until hot. Add onion, and sauté 2 to 3 minutes or until tender. Add pasta, snow peas, and pimiento. Combine sour cream, wine, and mustard in a small bowl; stir well using a wire whisk. Add sour cream mixture to pan. Cook, stirring constantly, 2 to 3 minutes or until thoroughly heated. Serve immediately.