Bring a very large pot of water to a boil. (Since I do not own a lobster pot, I used my two largest stock pots.) Kill lobsters, as described above (if desired), then plunge into boiling water. Boil for 10 to 11 minutes. Remove lobsters from pots, let cool briefly, then start cracking. Remove meat from lobster, chop coarsely and place in a large bowl.
Spread the lobster meat out in the bowl into a single layer. Season with kosher salt. Add tarragon mayonnaise to taste. To give you an idea, my three lobsters yielded 13.5 oz of meat, and I used a quarter cup of the homemade tarragon mayonnaise. Add lemon juice — I used about half a lemon — to taste. Gently mix the ingredients with a spatula. Taste. Adjust seasoning as necessary.
Toast hotdog buns, if desired. (My buns had been baked that day, so I did not toast them.) Spoon lobster meat into buns. Serve with additional wedges of lemon on the side.