Zest and juice the lemon to get about 2 tsp zest and 3 tbsp juice. Add both to a large mason jar. Add the olive oil, garlic, mustard, and sugar. Season to taste (I add 1/2 tsp salt & 1/4 tsp pepper). Seal and shake well to combine. Refrigerate while preparing the salad so the flavors can meld.
Bring 12 cups of water to a boil in a large pot. Once boiling, add 1 tablespoon salt and the orzo. Cook according to package directions. Drain, rinse under cold water for about 20 seconds, shake off excess water, and allow the pasta to cool completely.
Halve the tomatoes and olives. Finely dice the red onion (see note 1). Chop the parsley. Add the tomatoes, olives, onion, parsley, and feta to a large bowl.
Grill the corn if desired (see note 2). Cut the kernels from the cob and add to the bowl. The corn can also be added raw for extra crunch (this is how I like it).
Add the cooled orzo to the bowl. Pour the dressing over everything and toss well to combine. Taste and adjust with additional salt and pepper if needed.
Refrigerate for 30 minutes to 1 hour before serving. Toss again just before serving.
Video
Notes
Note 1: To mellow the flavor, soak the diced onion in cold water for 10 minutes. Drain well before adding to the salad.Note 2: Preheat grill to medium-high heat (about 400°F). Remove husks and silk from the corn. Rub each cob with about 1 teaspoon vegetable oil and lightly season with salt and pepper. Place directly on the grill grates and close the lid. Grill about 3 minutes per side, turning occasionally, for about 12 minutes total or until lightly charred. Remove and let cool before cutting off the kernels.Storage: Store in an airtight container in the fridge for 3 to 5 days. For best results, store the salad, dressing, olives, and red onion separately and combine only the portions you plan to eat right away. If meal prepping, I like to double the dressing and add a little more each day since the pasta absorbs the dressing as it sits and can become slightly dry.