Coat a large nonstick skillet with cooking spray; add margarine. Place over medium-high heat until margarine melts. Add shallots; saute 1 to 2 minutes or until tender. Add peas; saute 2 additional minutes. Stir in broth, vodka, and pepper; bring to a boil. Reduce heat, and simmer, uncovered, 3 minutes.
Combine milk and flour, stirring until smooth. Add to vegetable mixture in skillet, and cook, stirring constantly, until thickened and bubbly. Stir in smoked salmon. Remove from heat; set aside, and keep warm.
Cook pasta according to package directions, omitting salt and fat; drain well.
To serve, place pasta in a serving bowl; add salmon mixture, and toss lightly.