Combine gelatin and dry Vermouth. Heat gently until dissolved, and set aside to cool. Combine all other ingredients into gelatin mix, blending well. Pour into a 2-cup flat-bottom mold. Chill at least 3 hours or overnight.
In medium bowl, combine cucumber slices with green pepper strips. In measuring cup, combine rest of ingredients, mixing well. Pour over cucumber mixture, tossing to coat well. Refrigerate, covered, until well chilled--about 1 hour--tossing occasionally. To serve: Drain dressing from vegetables. Arrange vegetables attractively on large platter. To unmold mousse: Run a spatula around edge of mold; invert onto vegetables. Serve at once, with crackers as appetizer or as salad on bed of lettuce.