You need an LMIA from your employer, as well as a job offer or contract.
To be honest, you are not going to get an LMIA for a restaurant manager position as that can be easily filled by a Canadian, Permanant resident or a foreign student with a PGWP. LMIA is very difficult to get and most employers will not want to go through the hassle of getting it. They also have to prove that they cannot get any Canadian citizen or Permanant resident who is willing to do the job.
You need to discuss with your employer, remember an LMIA means that the employer cannot offer lower wages, LMIA is highly restrictive. If you think you have a shot, then you can discuss with your employer and see if he will get an LMIA. Do not that this will take up to 6 months.