Cook lobster rails in boiling water 6 to 8 minutes or until done.
Rinse with cold water.
Split and clean tails.
Cur lobster tail meat into 16 (1/4-inch-thick) slices.
Cover and chill.
Press cucumber between paper towels to remove excess moisture.
Combine cucumber, mayonnaise, vinegar, onion powder, dillweed, and crushed red pepper; stir well.
Cover and chill at least 1 hour.
Arrange bread on individual serving plates.
Spread 2 teaspoons cucumber mixture on each slice of bread.
Top each with a lettuce leaf, 2 tomato slices, and 8 slices of lobster.
Top with remaining cucumber mixture.