Dice the onion, tomatoes and jalapenos and dump into a big bowl with the corn (I like to scoop out the excess seeds and liquid from the tomatoes, but you don\'t have to!)
Add a pinch of salt, a pinch of chili powder and the juice of one lime.
Taste and add more lime and salt as needed!
You will want to use lots of salt. I normally put in two big pinches, which always seems like far too much but works perfectly. You do need quite a lot to balance out the sweetness of the corn. Same with lime juice - you\'ll use more than you think! It\'s never more than two limes, though.