Make the chile paste: Grind the onion, cilantro, jalapeño, and salt together in a blender until all the ingredients are very finely ground. Transfer to a bowl.
Cut each avocado in half. Cut each side by making 3 or 4 evenly spaced lengthwise cuts through the avocado flesh down to the skin, without cutting through it. Make 4 crosswise cuts in the same way. Scoop the diced avocado flesh into the bowl with the paste. Repeat with the remaining avocado halves.
Thoroughly mix the avocado and paste together. The paste is what will keep the avocado from browning.
Add the tomato, cilantro and white onion to the bowl and fold together.
Camp has been a part of my life for as long as I can remember. I started here at KenWood at age 8 as a Super Deb, and the rest is history. KenWood is where I discovered my love of all waterfront activities and karaoke.