Lentil Burger Salad Bowl

Name: Lentil Burger Salad Bowl
Ingredients: 1 10-ounce package frozen cooked brown rice (2 lightly packed cups); 5 tablespoons extra-virgin olive oil; 1 large onion, finely chopped; Kosher salt and freshly ground pepper; 1 teaspoon ground cumin; 1 15.5-ounce can lentils, drained; 1 teaspoon grated lemon zest, plus 2 teaspoons juice; 5 ounces baby lettuce spring mix; 2 medium carrots, shredded on the large holes of a box grater; 1 cup drained sliced pickled beets; 3/4 cup prepared tzatziki; Green olives, for topping