In a large mixing bowl, toss together the tomatoes, cucumber, and onion. Add the avocado, drizzle over the olive oil and lemon juice, and sprinkle over the parsley or cilantro.
Season with salt and pepper. Gently toss until everything is well combined. Serve relatively quickly.
Notes
Make Ahead Salad Recipe
I like to juice the lemon, and mix it with the olive oil, and chop up the onion and cucumber a day ahead. A few hours before I’m planning to serve this, I toss it all together along with the tomatoes, and then just before it goes on the table the avocados are cut and added and the dressing gets folded in. Each section of the process takes about 3 to 4 minutes, which is almost not even time worth counting.