For the quinoa filling: Combine the quinoa, salt, jalapenos, sweet potatoes and 2 cups water in a saucepan over medium-high heat. Bring to a boil, reduce the heat to low and cook until the quinoa is tender and the water has been absorbed, about 20 minutes. Cool slightly, and then fluff with a fork.
For the tacos and toppings: Warm the tortillas and fill each with some of the quinoa filling. Top with the shaved cabbage, tomatillo salsa, cilantro and a squeeze of lime.