For example, Hot Lap-Fastest Lap of 3...set your goal time as easy as allowed, achieve that time on lap 1, spend the next 2 laps doing 180 degree skids for as long as you desire. Just avoid the walls, and the game was cool with that. Even for Average Lap...setting a slow goal and doing enough skidding can reward more kudos than a fast time, drifting perfectly every turn, and even getting a 'no penalty' bonus. Another example: One-on-One race...give YOURSELF a 1min head start and spend that time skidding. Again, more potential kudos than doing it the 'stylish' way.
If I remember right, a Fastest Lap challenge was one of the 4 at the start of the game. So if you're hard up for kudos early on, there ya go... Do this enough to open up more of the game, and you can then just do the bare minimum of the other challenges without worrying at all about kudos. Of course you can still do it all the 'normal way', but you don't have to. And a 'retry' option would have definitely been nice in this case...
That all said... Don't get me wrong. The actual 'racing' part of the game is great fun and what keeps me coming back. The cars handle great and the visual detail is nice. So I'll usually end up spending hours just practicing a track, racing my ghost because I just have to get a new record! I'm always telling myself, "just one more lap."