In a medium saucepan, combine 1 1/2 cups of water and 1/3 cup of dried lentils. Bring to a boil, then reduce heat to low and let simmer for about 20-25 minutes, or until the lentils are tender. If you’re using canned lentils, skip this step and drain them before use.
While the lentils are cooking, heat 2 tablespoons of grapeseed oil in a large skillet over medium heat. Add the minced garlic and sauté for about 1 minute, until fragrant.
Add the cauliflower florets to the skillet along with cumin, turmeric, salt, and cinnamon. Stir well to coat the cauliflower with the spices, then add 3 tablespoons of water. Cover the skillet and allow the cauliflower to steam for about 10 minutes, or until tender.
Once the lentils are cooked, drain any excess water and add them to the skillet with the cauliflower. Stir everything together and let it cook for an additional 5 minutes to combine the flavors.
Warm the corn tortillas or taco shells according to package instructions. Spoon the lentil-cauliflower mixture into each tortilla, then top with diced tomatoes, fresh cilantro, sliced jalapeño peppers, and a dollop of sour cream or vegan yogurt.