Preheat the oven to 425°F (220°C).
Toss cauliflower florets with olive oil, blackened seasoning, maple syrup, and smoked paprika in a large bowl until well coated.
Arrange cauliflower in a single layer on a lined baking sheet and roast for 20–25 minutes, flipping halfway, until tender and slightly charred.
On a separate lined baking sheet, toss sweet corn and broccolini with olive oil, sea salt, and black pepper.
Roast corn and broccolini for 15–20 minutes until broccolini is tender and corn is caramelized; let cool slightly.
Place chopped kale in a large bowl and massage with a drizzle of olive oil and pinch of salt for 1–2 minutes until softened and darker in color.
Add roasted cauliflower, corn, broccolini, chopped jalapeños, cucumber slices, and avocado to the kale.
Drizzle generously with Green Goddess dressing and toss gently to coat all ingredients evenly.
Serve immediately while vegetables are slightly warm, garnished with extra herbs, cracked pepper, or lemon if desired.