Preheat the oven to 400ºF.
Cook the orzo according to the directions on the packet until al dente. Rinse the pasta under cold water to cool before making the salad. (Toss with a light drizzle of olive oil if you plan on having leftovers or making salad jars.)
Roast the chickpeas (optional): Rub the chickpeas between the layers of a dish or paper towel to remove excess liquid. Place the chickpeas onto a large, non-stick rimmed baking sheet. Toss with the lemon juice and zest, salt, and pepper. Roast for about 15 minutes, or until crispy and browned. Set aside to cool.
Drain tomatoes (optional): Meanwhile, transfer the chopped tomatoes to a strainer. Add a generous dash of salt and toss until evenly coated. Set aside over a bowl to drain. Reserve the liquid for the dressing.
Make the oil-free pesto: Meanwhile, add the basil, garlic, lemon juice, sunflower seeds, and ¼ cup water to a high-speed blender. Blend on high until smooth, adding the juice from the drained tomatoes, or more water as needed until the desired consistency. Add maple syrup, salt, and pepper to taste.
Make jars (optional): Place 4 (15-ounce) Mason jars in a row. Divide the dressing, orzo, cucumber, tomato, red onion, olives, chickpeas, and hemp hearts between each jar. Cover and refrigerate up to 4 days.
For serving:Jars: Invert the jar and shake it over a medium bowl. Mix to combine. Add salt, pepper, and more lemon juice to taste. Skip the jars and combine the orzo, tomatoes, cucumber, red onion, olives, hemp hearts, and dressing in a large bowl instead. Add salt and pepper to taste.