Preheat your oven to 200°C (400°F). Line a baking sheet with parchment paper for easy cleanup.
Drain and rinse the chickpeas, then toss them with 1 tablespoon of olive oil, cumin, paprika, salt, pepper, and cayenne if using. Spread them evenly on the prepared sheet.
Place the chickpeas in the oven and roast for 30 to 40 minutes, shaking the pan halfway through, until they are golden, crispy, and fragrant.
While the chickpeas roast, peel and dice the sweet potato into bite-sized chunks. Toss with 1 tablespoon of olive oil, a pinch of salt, and pepper.
Spread the sweet potato pieces on another baking sheet or the same one once chickpeas are done. Roast for about 25 minutes until caramelized and tender, with edges slightly browned.
Meanwhile, chop the cucumber, slice the radishes, and shred or slice the carrots. Arrange these fresh vegetables in two bowls for a colorful base.
Prepare the tahini sauce by whisking together tahini, lemon juice, minced garlic, and a pinch of salt. Add warm water gradually until the sauce is smooth, creamy, and pourable.
Once the roasted sweet potatoes are ready, let them cool slightly before adding to the bowls.
Assemble each bowl by dividing the roasted sweet potatoes and crispy chickpeas among them, then piling on the fresh veggie slices and halved cherry tomatoes.
Drizzle generously with the tahini sauce, letting it pool slightly over the ingredients for a rich finish.
Serve immediately for the best crunch and freshness, or let sit for 10 minutes to allow flavors to meld.