Hi, can i play Fool me Once when there is NO Discard pile, just to draw the card?

It's philosophical whether a discard pile exists when there are no cards discarded, but having one or more cards in the discard pile is not a prerequisite in playing the card, you only need to suffer the cost and be "during your activation", then perform the parts of the ability you can.

You also don't need to have any card in your command deck.

if idont have any cards ill just take the 2 hits instead....i was thinking clawdite with trusted ally to heal him for the Imps...