Add red lentils to a medium saucepan with 2 cups of water. Bring to a boil, then reduce heat and simmer for 10-12 minutes until lentils are soft and water is mostly absorbed. Drain any excess water and let cool for 5 minutes.

In a large mixing bowl, combine the cooled lentils, grated sweet potato, chopped onion, minced garlic, cumin, paprika, coriander, salt, pepper, fresh cilantro, and flour. Mix thoroughly until the mixture holds together when pressed. Let the mixture rest for 5-10 minutes.

Heat 2 tablespoons olive oil in a large skillet over medium heat. Scoop about 1/4 cup of mixture and gently form into patties with your hands. Cook for 3-4 minutes per side until golden brown and crispy.

While patties cook, make the sauce by blending avocado, cilantro, garlic, lime juice, yogurt, salt, and water in a food processor until smooth and creamy. Adjust consistency with additional water if needed.

Serve patties immediately while hot and crispy, topped with generous dollops of the creamy avocado cilantro sauce.