I believe the more natural way of saying this in English would be:
"You can open a restaurant."
"open" in the sense of start a business that receives the public.
If you have ever seen on a restaurant sign "Est'd 1912" or something to that effect, it means it was established in 1912. It tends to refer to the originator of the concept for that establishment or sometimes the owner/operator or builder.
Well, establish also means start. You can't open something without establishing it first. Establish seems natural as well. Besides, maybe that's just the way Mexicans talk.
Just an example. So let's say you don't know anyone trying to start up a restaurant. Perhaps you may encounter someone thinking about starting up a study group in Spanish, or establishing something completely different?
You can start a restaurant, and or, you can open a restaurant both imply the same thing and both are understood as the same thing. This is a good example of a word to word translation as opposed to a meaning to meaning translation. It's important not to forget that the primary function of language is communication, the conveyance of ideas and thought. Sometimes in our attempts to translate we opt out for the word to word style instead of the meaning to meaning and in doing so it is easy to lose the idea we are trying to express. Only my opinion...
Isn't Duolingo so encouraging? .....well, except when it makes you say "I am alone in the universe" or "We are dead men."