Combine all the ingredients* in a large glass or another non-reactive bowl. Season with salt and black pepper, to taste, and stir to combine.
Tip: Start with a very small amount of jalapeno pepper and taste before adding more.
Cover with plastic wrap and store in the refrigerator overnight or on the counter at room temperature for at least 30 minutes.
Serve with foil packet citrusy white fish or other minimally seasoned fish, chicken, or pork recipe.
This can also be served in place of regular salsa with tortilla chips. Enjoy!
Notes
*Soak the red onion in a cup of water for 10-15 minutes before using it to reduce its strong flavor and odor.
For best results, make this salsa the night before serving so the flavors have a chance to blend. This will also soften the peaches and onion to a nice consistency.