Whisk together vinegar, tarragon, salt and garlic in medium-size bowl until well blended. Gradually whisk in the oil until well blended.
Cook beans in large pot of boiling water until crisp-tender, about 8 minutes. Drain beans in colander; rinse under cold water to stop cooking. Blot beans dry with paper toweling.
Add green beans and lobster meat to dressing; toss to mix. Cover and refrigerate 2 hours or overnight.
To serve, let stand at room temperature for 30 minutes. Garnish with frilly lettuce if desired. Makes 6 servings.