Inspect the avocados to ensure they are ripe but still firm enough to maintain their shape when mixed.
Cut the 4oz block of feta into small cubes for the best flavor and texture.
In a medium-sized bowl, combine the diced avocado, cubed feta, diced tomatoes, red onion, minced garlic, chopped parsley or cilantro, olive oil, and vinegar. Sprinkle with salt to season.
Using a large spoon, gently fold the ingredients together until everything is evenly combined, being careful not to mash the avocado pieces.
To serve, transfer the dip to a serving bowl and enjoy it with crackers, chips, flatbread, or simply on its own.