Heat oven to 425. Line a rimmed large metal baking sheet with parchment paper. Toss the squash and cauliflower in the olive oil until evenly coated. Spread out the vegetables then roast for 15 minutes. Flip, then roast for another 10 minutes or until tender and lightly golden on the edges.
After flipping the roasted vegetables, bring the vegetable broth to a simmer in a small pot. Remove from heat, stir in the couscous, then cover for 5 minutes. Fluff with a fork then stir in the lemon juice, red pepper flakes, black pepper, and salt, to taste.
Spoon the cooked couscous into a medium-large dinner bowl. Top with the hummus, roasted squash and cauliflower, arugula, seeds, lemon, pepper, and salt. Enjoy!