Place an oven rack in the center of the oven; preheat to 450°F. Wash and dry the fresh produce. Peel the carrots; cut on an angle into ½-inch pieces. Halve and peel the onion; cut into ¼-inch-wide wedges, separating the layers. Snap off and discard the tough, woody stem ends of the asparagus; cut on an angle into 2-inch pieces (keeping the pointed tips intact). Place in a bowl; drizzle with olive oil and season with salt and pepper. Toss to coat. Pick the mint leaves off the stems. Halve the lime crosswise. Medium dice the cheese. In a medium bowl, combine half the yogurt, the juice of 1 lime half, and as much of the harissa paste as you'd like, depending on how spicy you'd like the dish to be; stir to combine. Add the diced cheese. Season with salt and pepper; stir to combine. Set aside to marinate, stirring occasionally, at least 10 minutes.

Line a sheet pan with foil. Place the carrot pieces and onion wedges on the foil. Drizzle with olive oil and season with salt and pepper; toss to coat. Arrange in an even layer on one side of the sheet pan. Roast 10 minutes. Leaving the oven on, remove from the oven. Carefully arrange the seasoned asparagus in an even layer on the other side of the sheet pan of partially roasted carrots and onion. Return to the oven and roast 6 to 7 minutes, or until the vegetables are lightly browned and tender when pierced with a fork. Remove from the oven.

Meanwhile, in a medium pot, heat 2 teaspoons of olive oil on medium-high until hot. Add the couscous; season with salt and pepper. Cook, stirring constantly, 1 to 2 minutes, or until lightly toasted. Add 4 cups of water (carefully, as the liquid may splatter). Heat to boiling on high. Once boiling, cook, uncovered, 4 to 5 minutes, or until tender. Turn off the heat. Drain thoroughly.

Meanwhile, in a medium pan (nonstick, if you have one), heat 2 teaspoons of olive oil on medium-high until hot. Reserving the marinade, add the marinated cheese in an even layer. Cook, without stirring, 2 to 3 minutes, or until browned. Continue to cook, stirring occasionally, 2 to 3 minutes, or until browned and slightly crispy. Turn off the heat. 

In a large bowl, combine the remaining yogurt, reserved marinade, and the juice of the remaining lime half. Season with salt and pepper. Add the arugula, cooked couscous, roasted vegetables, half the mint leaves (tearing just before adding), and a drizzle of olive oil; season with salt and pepper. Stir to thoroughly combine. Taste, then season with salt and pepper if desired. Serve the finished couscous and vegetables topped with the cooked cheese. Garnish with the remaining mint leaves (tearing just before adding). Enjoy!