At the risk of being hyperbolic (which I've NEVER been known to be), this is my favorite thing I've made all summer. If I've got a good tomato sitting around, my default is to make salsa with lime and cilantro. This was refreshingly different. We had it over mushroom and kale enchiladas, which were truly, truly born of a fridge-cleaning. So much so that I couldn't recreate them if I tried.
But if you want to recreate this, chop up one lovely, juicy beefsteak tomato. Cut the kernels from two ears of corn, and quickly saute them in olive oil (about 2 minutes), just until they don't taste raw anymore. In a medium bowl, combine the tomato and corn with chopped fresh jalapeno or red chile to taste, 1 Tb. apple cider vinegar, a handful of finely chopped green onions, 1/2 Tb. sugar, and kosher salt. Gently mix. Yum. Salivating as I type this.