Kitchen cabinets are painted blue, can I repaint them without sanding

They should be striped and cleaned first

Yes, with enough coat of paint or even Kills you can do that but it looks better to sand them first because the paint t will glide better, absorb better and gloss better and will be less likely to chip later.

Hello. You can repaint over the existing paint, but the paint might not adhere as well. If you don't want to lightly sand them make sure they are very clean with no residue on them. Then prime them, and paint.

You must scrub and sand.

It's not really a question if you CAN paint without sanding, it's a question if you WANT to paint without sanding. Sanding helps the paint stick better and the final finish look better - especially if you sand lightly between coats. Does it take longer? Yes. Will you have to do it more often if you don't sand? Yes. It's your choice.