Cook lentils by placing lentils and water in a small saucepan. Bring to a boil over high heat. Once boiling, lower heat to medium-low, place lid on pot, and allow to simmer for 20-30 minutes.
While lentils are cooking, dice/chop walnuts (1.5c), shallots (2), garlic (2), and jalapeno (1).
Heat a medium-sized skillet (or cast-iron skillet) over medium heat. Once hot add oil (1Tblsp).
Once oil is hot, add walnuts, shallots, garlic, and jalapeno, and cook until fragrant and onions are translucent, approximately 3-5 minutes.
Add cooked lentils, salsa (1/4 c), juice from lime (1/2 lime), and spices.
Turn heat off, cover, and let sit for 5-10 minutes to allow flavors to meld.
Serve immediately with all your favorite taco toppings!
Store leftovers in the fridge for 4-5 days.
