Prepare the lobster. Cut off claws and split in half lengthwise. Split the lobster lengthwise, from head to tail. Discard the stomach area. Cut into pieces. Place in a bowl and season with salt and pepper. Lightly coat with potato starch, shaking off any excess starch.
Preheat peanut oil to 400 degrees F.
Deep-fry the lobster pieces for 1 1/2 to 2 minutes. Remove from oil and drain on plate lined with paper towels. Reserve.
Prepare the bok choy, snow peas and leeks. Reserve.
To prepare the sauce: In a wok, over high heat, combine the oil, sugar, fermented black beans and garlic. Season with salt and pepper. Stir-fry for 10 seconds. Add sherry and reduce by half. Add all the prepared vegetables and continue to stir-fry for another 10 seconds. Deglaze with lobster stock and add the reserved lobster pieces. Continue to stir-fry another 20 seconds. Transfer to a heated plate and arrange the lobster pieces decoratively.