Heat oven to 400 F. Arrange sweet potatoes (skin side down) and onions on baking sheet. Drizzle with oil ensuring good coverage. Bake 10 minutes. Remove from oven, flip, and add broccoli, drizzling with more oil and seasoning well with salt & pepper. Bake another 8-10 minutes, remove from oven, add kale. Drizzle with a touch more oil and season with salt & pepper. Bake another 4-5 minutes then set aside. Meanwhile, heat large skillet over medium heat. Drain chickpeas, pat them dry, place in a bowl, and toss with seasonings. Add 1 T oil to the hot skillet, then toss in the chickpeas and sauté, stirring frequently, until they brown (about 10 minutes). Make the dressing by whisking together tahini, maple syrup, lemon juice, and enough hot water to reach desired consistency. To serve, slice sweet potatoes into bite-sized pieces. Divide veggies between 3 serving bowls and top with chickpeas & tahini dressing.