In a medium saucepan, bring the lentils to a boil with 3 cups of water. Add garlic, chili powder, and cumin. Reduce heat and simmer loosely covered. Cook until lentils are tender, about 35-40 minutes.
In a large skillet, heat canola oil over medium heat. Add peppers and onions. Saute until soft and starting to brown. Add pepper mixture to the lentils and stir to combine.
To make the quesadillas:
In a skillet, carefully place the quesadilla and cook about 3-4 minutes or until brown. Turn over carefully, and brown the other side, making sure the cheese is melted throughout.
Keep the quesadillas warm in an oven on low heat while you continue to cook the others. Cut into 3 wedges and serve immediately.