Saigon Grill
Saigon Grill is a Vietnamese restaurant on Amsterdam Avenue at 90th St. Thus, it's not strictly in Morningside Heights, but it does normally deliver to the area.
Or at least, it used to. At the moment, the restaurant has suspended its delivery service due to an ongoing labor dispute. The workers were paid under minimum wage and were instructed to work in conditions that are alleged to have been unsafe.
Map
<googlemap lat="40.790233" lon="-73.973168" type="map" zoom="16" width="500" height="300" controls="small"> 40.790233, -73.973168, Saigon Grill (Vietnamese) - rough location </googlemap>