Preheat the oven to 220°C (425°F). Line a large baking tray with baking paper.
Cut the 1 head cauliflower into bite-sized florets. Pat the 1 400 gram can chickpeas dry with paper towel after draining and rinsing.
Place the cauliflower and chickpeas into a large mixing bowl. Drizzle over the ¼ cup olive oil, then sprinkle over the 1 tablespoon smoked paprika, 1 teaspoon garlic powder, ½ teaspoon chilli powder, Salt and pepper. Toss well until everything is evenly coated.
Spread the cauliflower and chickpeas onto the prepared baking tray in a single layer, ensuring they aren't overcrowded. Roast for 30 minutes, tossing halfway through, until the cauliflower is tender and caramelised and the chickpeas are golden and crisp.
Meanwhile, prepare the garlic tahini dressing. Add the ½ cup tahini, 3 tablespoons lemon juice, 2 cloves garlic, 1 tablespoon honey, ½ teaspoon salt and ⅓ cup water to a blender or small food processor. Blend until smooth and creamy. If the dressing is too thick, blend in a little more water, one tablespoon at a time, until it reaches your desired consistency. Taste and adjust the seasoning or add more lemon juice if needed.
Arrange the 250 grams mixed salad greens, ½ cucumber and ¼ red onion in a large serving bowl.
Once the cauliflower and chickpeas have finished roasting, allow them to cool for 5 minutes before adding them to the salad. Add the 1 avocado, drizzle over enough of the garlic tahini dressing to lightly coat the salad, then gently toss everything together.
Drizzle with extra garlic tahini dressing and serve with lemon wedges, if desired.