Preheat oven to 375°F.
Combine the zucchini, squash, red bell peppers, both onions and corn in a large bowl. Add the cumin, Harissa seasoning, Mexican chili powder, salt and olive oil. Gently toss until the vegetables are completely coated.
Lay the vegetables on two large foil lined baking sheets. Do not over-crowd the vegetables on the pans, or they’ll steam and not roast which would be a damn shame. Lay each vegetable flat against the pan because that contact point is where the yummy roasting magic happens.
Roast the vegetables for 25-35 minutes. Flip the the vegetables over after 15 minutes and add the black beans. Remove the vegetables when tender and browned.
Heat the tortillas. I used a skillet over medium heat and warmed them stove-top.