Make the dressing by combining 1 tbsp extra virgin olive oil, 1 tbsp lemon juice, 1/2 tsp oregano, 1/4 tsp sea salt, and 1/8 tsp black pepper in a small jar or bowl; shake or whisk until well combined, then set aside.
Warm the cooked rice if desired, then place about 1 cup of warm rice into a serving bowl.
Add about 1/3 cup hummus on top of or beside the rice.
Arrange the sliced tomato, peeled and sliced cucumber, thinly sliced red onion, and halved kalamata olives around the hummus and rice.
Drizzle the prepared dressing over the vegetables and hummus.
Garnish as desired (for example with toasted pita or feta) and serve immediately.