If you want to minimize cleanup and effort, just use a rice cooker.
Costs 30€
Put in rice and lentils at a ratio of your chosing, cook with oil and salt
Optionally spices and tomato paste
Put in frozen veggies either in a steaming basket or directly in the rice
Chuck in an onion (quartered if you're lazy) and some garlic
Yoghurt on the side
Congratulations you now have a healthy, cheap meal you can make at home or at work. If you eat directly out of the cooker you only need to clean your spoon. No cutting board needed either.
I'm a pretty good cook, but I don't think there's enough here to get it done. Do rice and lentils take about the same amount of water to cook? How much oil?