Step 1

Pour ¼ cup of the lemon juice into a mixing bowl. Cut the avocados in half, remove the pit, peel them (or scoop them out with a spoon), and cut in ½-inch dice. Immediately add the avocados to the lemon juice and toss carefully. Add the cherry tomatoes and red onion and toss again.

Step 2

In a small glass measuring cup, whisk together the remaining 2 tablespoons of lemon juice, ¼ cup olive oil, ½ teaspoon salt, and ½ teaspoon pepper.

Step 3

Pour enough of the vinaigrette over the tomato and avocado mixture to moisten completely. Add the arugula, add more vinaigrette, sprinkle with 1½ teaspoons salt and ½ teaspoon pepper, and toss well. Taste for seasonings (you want the salad well seasoned!) and serve at room temperature.