Here's an example of remove:

db.remove(id);

Passing an ID removes the document with the given ID.

If you have more than one document to remove, you could iterate across all documents, the way the following code does, removing each document in turn:

db.all(function(err, doc) {
  for(var i = 0; i < doc.length; i++) {
    db.remove(doc[i].id, doc[i].value.rev, function(err, doc) {
      console.log('Removing ' + doc._id);
    });
  }
});

This is a more complex use of remove; it takes the document's ID, the revision of the document, and a callback function, which logs to the console the ID of each document that was removed.