Method:
For the rice and lentils, heat olive oil in a large, heavy pot over medium-high heat. Add onion and garlic and cook until translucent. Stir in lentils, then add broth. Bring to a boil, reduce heat, cover, and simmer for 20 minutes. Add rice and continue to simmer, covered, adding more broth or water, if necessary, until all liquid is absorbed and lentils and rice are both tender, about 20 minutes more. Set them aside off the heat, covered, for 5 minutes, then stir in vinegar and dill. Set aside until ready to serve.
For the cucumber salad, mix yogurt and tahini in a medium bowl until smooth. Stir in feta cheese and red onion, then gently fold in tomato, cucumber, and salt and pepper. Garnish with mint and serve with dilled rice and lentils.