Fire up your Traeger and preheat it to 450 degrees Fahrenheit. Let it come up to temperature fully before you put anything on the grates. We used our hickory pellets and the smoky flavor was incredible, but cherry or apple wood pellets would be beautiful with the peaches too.
While the Traeger is heating up, prep your fruits and vegetables. Halve and pit the peaches. Halve the tomatoes. Slice the jalapeños in half lengthwise and remove the seeds if you want less heat. Leave the green onions whole and smash the garlic cloves just slightly so they get some good smoky flavor on them.
Place the peaches, tomatoes, jalapeños, green onions, and garlic (wrap in foil) directly on the grill grates. Close the lid and let everything smoke for about 30 minutes. You are looking for slight char marks on the peaches and tomatoes, and the skin on the jalapeños should start to blister. It will smell absolutely amazing and your neighbors will absolutely wander over.
Pull everything off the Traeger and let it cool for at least 15 minutes. I cannot stress this enough. If you skip this step and go straight to blending, you will have a steam explosion situation and hot salsa everywhere. Ask me how I know. (I will not tell you. Just trust me and wait.)
Here is where you get to decide what texture you want. For a chunkier salsa, use a knife and chop everything by hand. For a smoother restaurant-style salsa, pulse everything in a food processor or blender. I like a middle ground where I pulse it just a few times so it is chunky but scoop-able.
Add the smoked peaches, tomatoes, jalapeños, green onions, and garlic to your food processor. Add the fresh cilantro, apple cider vinegar, lime juice, salt, and black pepper. Pulse until you reach your desired consistency.
This is the most important step and also the most fun. Taste your salsa and adjust from there. Need more acid? Add a little more lime juice or apple cider vinegar. Want more heat? Toss in a little more jalapeño. More salt? Go for it. Trust your palate here.
Transfer the salsa to a bowl or jar and refrigerate for at least 30 minutes before serving. The flavors deepen and come together so beautifully after it has had some time to rest. Serve cold with your favorite tortilla chips or use it as a topping for grilled meats, fish tacos, or burrito bowls.