In a large, heavy pot, bring 2 gallons of water, the bay leaves, onions, 1 teaspoon of salt and peppercorns to a boil. Add the lobsters to the water and simmer, covered, for 10 - 12 minutes. Transfer the lobsters with tongs to a colander and rinse under cold running water. Drain and let cool.
When cool enough to handle, break off the claws from one of the bodies and crack to remove the meat. Twist the tails from the lobster and discards the bodies. With kitchen shears, cut the underbelly of the lobster and remove the tail meat. Cut the tail meat into bite sized pieces, and reserve the whole claw meat and set aside.
In a medium bowl lightly dress the mesclun greens with the olive oil and 1/4 teaspoon salt. Divide the mixture among 4 salad plates.
Cut the avocados in half and remove the seeds and skins. Place 1/2 an avocado on each salad plate.
Transfer the lobster meat to a medium bowl. Add the mayonnaise, lemon juice, truffle oil, shallots, chervil, truffle and remaining 1/4 teaspoon salt, and toss lightly to just combine.
Divide the lobster salad among the 4 avocado halves, and garnish with chives. Serve.