What are the rate limits for the new Desk APIs? And is there a way to get tickets by ticketnumber?

What are the rate limits for the new Desk APIs? And is there a way to get tickets by ticketnumber?

Hi. I have 2 questions:

1) What are the rate limits for the new Desk APIs? I cannot find them in the official documentation.

2) Is there an API method to get a ticket by ticket number? Currently I have to make many, many calls to get all tickets (since pagination is limited to ~50 items per call) and then exhaustively compare the ticket number against all tickets. This can cause problems because there are a lot of tickets and I might get rate limited.

Many thanks.