Place the eggs in a small pot and add enough water to cover them. Bring to a boil over medium-high heat, then remove the pot from the heat, cover, and let the eggs sit for 10 minutes. Remove the eggs from the hot water and let cool completely.
Peel the eggs and cut them in half lengthwise. Scoop the yolks into a medium bowl, and add the avocado and lime juice. Using a spoon, mash until the mixture is as smooth as possible. Stir in the cilantro and salt.
Scoop the egg yolk filling into a reusable plastic sandwich bag and use scissors to snip off one of the corners, making a half-inch hole. Pipe the filling into the empty wells of the halved eggs. Top with chopped tomatoes and a sprinkle of chili powder.
Notes
Storage: Since this recipe contains avocado, it's best to eat these deviled eggs within a day or two of making them. The lime will help keep them from oxidizing and turning brown, but they won't last as long as traditional hard boiled eggs in the refrigerator.