Over the years, many great casual restaurants around New Orleans got their starts by selling sandwiches to construction workers. The widespread destruction in the eastern half of the city during Katrina brought a lot of crews to the area. Almost from the beginning, they lined up at the Castnet, one of the first restaurants to open in The East. The high ground along the lakefront was less badly battered, and owner Kent Bondi got right to work making poor boys. He's still at at, along with his rebuilder clientele. But the food is good enough to attract a good many people who are just looking for a good meal.
Hayne Boulevard has been the address of many great seafood restaurants for nearly a century. Most of them were gone by 1988, when Kent Bondi bought an existing seafood retailer and began frying oysters, shrimp, and fish. He and his neighbor Walker's BBQ were a magnet for eaters, and were doing pretty well when Katrina came. When it went, the place went ballistic.
A couple of years ago Walker's and Castnet rebuilt their place, making it no fancier but nicer looking. The two restaurants share a dining room, which is entirely self-service.
Avoid the period an hour before or after noon, when the crowds are heaviest.