You'll want to use something like:
while read directory
do
find "$directory" -size +1M -exec stat --format="%U (id: %u), file: %n" {} \;
done << EOT
/path/to/folder 1
/path/to/my folder 2
EOT
The +1M would look for files over 1M.
The stat format would show a username, its user ID and corresponding file name, for anything find would have matched.
Following up on comments, say I want to filter these on modification time, such as find should not match any file that got modified in the last 24 hours, then I could use:
find "$directory" -size +1M -mtime +1 -exec stat --format="%U (id: %u), file: %n" {} \;