Heat oil in a large stockpot over medium heat. Add onions to the pot and saute until translucent.
Add garlic, chili powder, cumin, paprika and oregano to pat and continue to saute until fragrant about 2 minutes.
Add lentils, tomato sauce and stock to pot and stir to combine. Return to a boil, once boiling reduce heat to low and simmer 35 to 40 minutes or until lentils are tender, add in more stock as needed to prevent lentil from sticking to bottom of pot.
Taste and season with salt as needed.
When lentils are done, heat a large skillet over medium heat or heat an electric griddle to 350 degrees.
Spread about 3 tablespoons of lentils over one half of tortilla, sprinkle cheese over lentils, fold other half of tortilla over lentils and cheese, brush with a bit of olive oil and place in skillet or place on the griddle. Cook on each side 3 to 4 minutes or until golden brown.
Transfer to plate, serve with a scoop of guac, salsa and garnish with cilantro.