“My long-term goal is to open my own restaurant.”

You are talking to a person you just met at a party. You're telling him about your job and your career goals. You say:

My long-term goal is to open my own restaurant.

(one's) long-term goal

A "long-term" goal is a goal that someone plans to achieve several years in the future. Usually we think of a long-term goal as something that will happen in about 2-15 years.

Of course, you can also talk about a "short-term goal", which is something you want to accomplish in a few weeks or in a year or two.

(one's) goal is to (do something)

When you describe your goals, you say "my goal is to ___":

My goal is to have it finished by the end of July.

You can also use similar words like "dream" or "plan" in the same way:

His lifelong dream was to become a writer.

My plan is to get into law school and study Environmental Law.

open a (store)

Use the word "open" to describe starting a store or restaurant:

Did you see that they opened a new Apple store near Lincoln Center?