Lets say you have KsKd, you raise 4x/5x BB preflop and the flop comes Kc5h4c. How do you play this?

Whenever I'm in a situation like this I always make a big bet like 60-100% of the pot, because I'm scared of getting beat by a flush or a straight on the river. So you're making them pay to play if they do have a flush or straight draw. Is this the correct thing to do or do you want to extract as much out of the hand as possible? And therefore bet a bit smaller? Am I paranoid to think that a flush or straight will come or should I make an aggresive bet?
The straight may seem very unlikely, but at low limit poker, people are always making calls with hands like 67s or even ludicris hands like A3o and the the turn shows a 2 and you're screwed.

How should I play this hand? Also, how should I play flopping the nut flush?

Last week I was dealt KJs and the flop shows AT5s, so I have the nuts and I'm one card away from a Royal Flush. I decide not to raise and another player raises a small amount. 3 people in the hand and me and the other guy call. Then a Ten comes down. So now, the nuts is a full house, but I didn't think anyone had tripled or 2 paired on the flop so I wasn't worried. Don't raise much and the next card comes down. It's a 9. I end up going allin and the other guy had T9 and wins the hand. I'm out of the SnG. I should have raised big on the turn right? What about on the flop though? What should I have done?