While the water is coming to a boil, dice your tomatoes and cucumbers into uniform 1/2-inch pieces—this size ensures they'll hold their texture and distribute evenly throughout the salad. Finely dice the red onion into 1/4-inch pieces so the flavor distributes without overwhelming any single bite. Measure out the olives, feta, dill, and all your dressing ingredients into separate small bowls. I like to prep all my vegetables first so they can sit undressed without getting watery—it keeps the salad crisp.
Bring a large pot of salted water to a boil and add the orzo. Cook for 8-10 minutes until the pasta is tender but still has a slight bite to it—you want it soft enough to absorb the dressing but firm enough not to become mushy. Stir occasionally to prevent sticking. While the pasta cooks, you can whisk together your dressing ingredients in a separate bowl.
In a small bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, salt, and pepper until well combined. The acid from the lemon juice will emulsify slightly with the oil, creating a light vinaigrette. Let it sit while the pasta finishes cooking so the flavors can meld together.
Drain the cooked orzo in a colander and rinse thoroughly with cold water until completely cooled—this stops the cooking process and prevents the pasta from becoming mushy. Transfer the cooled orzo to a large serving bowl and immediately add the prepared vegetables (tomatoes, cucumbers, red onion, olives), feta, and dill from Step 1. Pour the dressing from Step 3 over the mixture and toss gently but thoroughly until everything is coated. I recommend dressing the salad right after the pasta cools so it absorbs all those Mediterranean flavors while still slightly warm.