You can cook the lentils in a pot on the stove, but I used an Instant Pot. Simply add the dry lentils, water, salsa, chili powder, cumin, garlic, onion and salt to the Instant Pot, secure the lid, set for pressure cook for 10 mins. Make sure you let the pot sit for 15 minutes after cooking before you vent the steam.
When the lentils are finished, scoop them into a casserole dish, top with cheese, red pepper, tomatoes, black olives and green onion. Broil in the oven for about 5 mins, just enough for the cheese to melt.