Adjust rack to top position and preheat oven to 425. Wash and dry produce.

Peel and quarter sweet potatoes lengthwise; cut into ½-inch-thick quarter-moons. Remove and discard any large stems from kale; chop into bite-size pieces. Drain and rinse beans; transfer to a large bowl and mash about half the beans, leaving some whole. Zest and quarter lime.

Toss sweet potatoes on a baking sheet with a drizzle of oil, half the Mexican Spice Blend (you’ll use the rest in the next step), and a pinch of salt and pepper. Roast on top rack until browned and tender, 18-20 minutes.

Meanwhile, heat a drizzle of oil in a large pan (for 4 servings, work in two batches or use two large pans) over medium-high heat. Add kale, beans, stock concentrates, garlic powder, remaining Mexican Spice Blend, and ¼ cup water (⅓ cup for 4). Cook, stirring occasionally, until liquid has slightly reduced and kale is wilted, 3-5 minutes.

Remove from heat; stir in juice from one lime wedge (two wedges for 4). Season with a pinch of salt and pepper to taste.

While veggies cook, in a small bowl, combine mayonnaise with juice from one lime wedge (two wedges for 4 servings) and as much lime zest as you like.

Wrap tortillas in damp paper towels and microwave until warm and pliable, about 30 seconds.

Spread a thin layer of guacamole on tortillas. Fill with kale and bean mixture and sweet potatoes. Spoon lime drizzle over top and garnish with crispy fried onions.

Divide tacos between plates and serve with remaining lime wedges on the side.