We try to go to the Delta most weeks and have been to nearly all the restaurants in the first and second section. Unfortunately I haven't been to Atelier Chez Lissie for many years so can't comment on how it is now.
You can get boats (lancha colectivas) from the Terminal Fluvial de Tigre which is next to the last stop on the Mitre train line. You would need to study a timetable to see which ones pass by the Rio Capitan for the Atelier Chez Lissie.
There are also many booths in the port selling tickets for restaurants that run transport for their customers. Water taxis are also available.
The best way is obviously to own a boat which gives you better flexibility on time and location.
Restaurants on the Delta tend to be expensive but a great escape from the city.