Hmmmm seafood salad… Hmmmm prosciutto….
If you had to choose between one of the two, what would you like to eat?

“Ecco” is used very often in TV to point someone’s attention to something.

“Eccoli” means “Here they are” referred to something plural, also people or animals.

I could for example be impatiently waiting for some people saying to Cinzia
Dove sono, dove sono? - Where are they, where are they?
When she sees them coming she could say
Eccoli! - There they are! / Here they are!

While “qua” and “qui” mean “here”

I hope these few examples help you out.

Ciao
Marco