PREP SQUASH: Preheat the oven to 425 degrees F. Peel the squash and chop into bite-sized (1-inch) even cubes. Toss the squash with the 2 tablespoons olive oil, 1/2 teaspoon (each) of salt, chili powder, paprika, cumin, garlic powder and 1/4 teaspoon pepper. Spread evenly on a very large sheet pan. You don't want squash pieces overlapping each other or they'll steam instead of roast, so use 2 sheet pans if needed.
BAKE SQUASH: Place the sheet pan(s) of squash in the oven for 10-15 minutes. Remove from oven, toss around and return for another 10-15 minutes or until caramelized and crisp tender. (Bake time varies a lot depending on how ripe the squash is, actual temperature of oven, and the actual size of pieces; I cut the pieces pretty small and spread them out a lot on a dark sheet pan so they roast for 10 minutes, flip, and another 10 minutes is perfect!).
BEANS: Meanwhile, drain and rinse the beans. Once the squash is tender, remove the sheet pan and mix the drained beans with the squash. Toss to combine and warm the beans.
SAUCE: While the squash is baking you can also prepare the sauce. Zest and juice 1 lime to get 3 tablespoons juice and 1/4 teaspoon zest. Add the juice and zest to a bowl along with 1/2 cup mayo, 1/8 teaspoon cumin, 1/4 teaspoon paprika, and 1/2 teaspoon chili powder. Add 1 teaspoon Sriracha and a generous pinch of salt and pepper. Whisk together with a fork until smooth.
ASSEMBLE: Char, grill, or warm the tortillas and top with the kale slaw (or coleslaw or broccoli slaw), a big scoop of the squash and beans, and whatever toppings you'd like (we love avocado and cilantro!). Drizzle on fresh lime if desired and add a few spoonfuls of the sauce to each taco. Enjoy while hot!