That flop is too ragged to assume one of your opponents doesn't have an ace because they checked.  I'm pretty comfortable checking an ace there against two opponents, of course, betting an ace for value there is pretty reasonable too.  Whether I bet an ace there depends a lot on how I've been playing and the opponents in the hand with me, but I think I prefer to check the ace, generally speaking.  I feel like checking the ace makes it more likely that I will get two streets of value.

If I was the preflop raiser I'm going to c-bet that flop close to 100% of the time with KK  to represent an ace, if one of my opponents calls I'm going to go into pot-control mode and most likely check back the turn prepared to call down on the river, depending on how the board runs out.  The problem here is you're out of position so it's going to be a little tough to control the pot, but I'd absolutely take a stab at it on the flop.

I'm a microstakes player, playing mostly $5 MTTs, so take my opinion with a grain of salt, but in the micros you get a s-ton of players all stoked to call a raise with any suited ace and seeing them show up with an unsuited ace-rag is never a surprise.  So, when I'm deep stacked with KK I'm going to play very cautiously if an ace comes on the flop.  Any more than two other players in the hand I'm very likely to just check/fold the flop, maybe it's bad to give up so easily, but one of those donks almost always has an ace.