Select peaches at the peak of ripeness. Blanch peaches in boiling water for 30 seconds, then transfer to an ice bath. Remove the skins and dice the peaches into 1/4-inch cubes.
Combine diced peaches with finely diced red onion, minced jalapeños, and diced bell pepper in a medium bowl.
Gently fold in the chopped cilantro, lime juice, honey, salt, and cumin.
Allow your spicy peach salsa to rest for at least 30 minutes in the refrigerator for flavors to meld together. If using avocado, add it just before serving.
Taste and adjust seasonings if necessary before serving.