Adapted from Meeru Dhalwala and Vikram Vij. It is peach season here, so I added peaches to this salsa. I would not hesitate to use other seasonal fruits throughout the year, or even other veggies, like roasted butternut squash. If you do not add a sweet fruit or veggie, consider that you might need to add a pinch of sugar, and if you add something tart, like fresh cranberries, you will certainly need to add sugar.
Prepare the red onion and let it soak. Drain.
Toss all of the ingredients together. Place in an airtight container and chill until needed.