Kourtney Kardashian Feeling Fishy Post-Birth

The Kardashian sister that's not Kim or married to Larmar Odom finally popped out her kid on Monday ... and once she regained her strength, all she wanted was a tuna sandwich.

We're told once Kourtney was feeling better, she dispatched sister Kim to Nate 'n Al -- a popular deli in Beverly Hills.

The order: One tuna sandwich and one turkey sandwich for Kourtney and her baby daddy Scott Disick to split.

Talk about a belly full...