Heat oil in a pan on medium heat. Add onions and jalapenos and saute for 2 - 3 minutes, stirring occasionally. Add garlic and saute for another 2 - 3 minutes, stirring occasionally.
Stir in black beans and cumin. Simmer for 5 minutes, Add in lentils and continue simmering for another 5 minutes.
In a separate pan prepare rice according to package instructions.
Add in can of Rotel and Fire Roasted Diced Tomatoes. Simmer for 10 minutes more, stirring occasionally until lentils have softened and liquid is reduced.
Top with half of cotija cheese and half of cilantro.
Heat grill and cook empty peppers on their sides for 2 - 3 minutes on each side until there are char marks on all sides.
Layer 1 - 2 tablespoons of rice in the base of each pepper. Fill the peppers to the top with pan mixture (lentil, black bean, tomato mixture). Stand stuffed bell peppers up on grill, top with a tablespoon of cotija cheese. Cook for another 3 - 4 minutes until cheese is melted. Note: If using poblanos you will have to cook on their sides unless you have a device to stand them up.
In each plate, layer a small bed of rice. Place stuffed pepper on the bed of rice. Top with remaining cotija and cilantro. Spoon in the avocado. Add any additional desired condiments (i.e. sour cream, hot sauce, etc.)