Drop table or truncate table? (e.g. do you want to have the table removed from the database or to have all records in that table deleted?)
Anyway, you can directly fire SQL statements using the psql command (when you are running m2ee). This opens a prompt where you can fire SQL Statements, like SELECT, UPDATE, DELETE and TRUNCATE (I guess).
Of course you should be carefull using TRUNCATE and DROP TABLE commands :---)
Hope it helps!
Edit: If your goal is to restore the database and your problem is that it fails... I think you can best use the commmand emptydb to empty the database and then use restoredb