Slice the squid so it lays flat then lightly score both sides in a crisscross pattern. Cut into bite-sized square pieces.
Place the squid along and lemon juice in a bowl. Leave to marinate for 10 minutes while you prepare the salt and pepper mix.
In a shallow bowl mix together the cornstarch, pepper, salt, and sugar.
In a separate shallow bowl lightly whisk the egg whites with a fork.
Dip the squid pieces in the egg mixture then gently toss through the salt and pepper mix, shaking off any excess.
Fill a wok, skillet, or pot with a maximum of 1/3 oil then heat to 350 degrees F (180 degrees C).
In small batches, add the squid and cook for about 1 minute or until lightly browned. Remove and rest on a paper towel to drain. Serve with tartar sauce.