Is it possible to retrieve a list of all users that liked a tweet?
No, the API only supports accessing the most recent 100 liking users.
Updated response 20th Jan 2022:
This has just been announced in the Twitter API v2.
Previously, you were limited to the 100 most recent Likes or Retweets with these endpoints. We heard your feedback that this was too limiting and have updated these endpoints to now return all results. To retrieve a complete list of Likes and Retweets, you can now use pagination.
Now, you can use the v2 Likes lookup endpoint: GET /2/tweets/:id/liking_users
and get the full list (with pagination).