In an upright blender, combine all of the ingredients for the spicy cumin garlic drizzle. Blend on high until you have a smooth, liquid-y mixture. Check for seasoning, adjust, and set aside.
Put your pot of rice on if you haven't got any cooked rice on hand. Place the cut sweet potatoes in another medium saucepan and cover them with water. Bring the sweet potatoes to a boil over medium heat and simmer until a knife just goes through when you try to prick one, about 10 minutes. Drain and set aside to cool slightly.
In a medium bowl, toss the black beans with a hearty pour of the spicy cumin garlic drizzle, the diced red onions and almost all of the cilantro. Season them with salt and pepper, toss once more, and set aside.
Preheat your grill to high. Skewer the sweet potatoes onto the bamboo sticks, making sure you don't weigh them down too heavily. Place skewers on a dinner plate along with the pieces of red bell pepper. Pour some of the spicy cumin garlic drizzle on top and lightly toss everything to coat. Grill sweet potatoes and red peppers until char marks appear and vegetables have softened slightly, about 10-12 minutes total. Remove from the grill and cut peppers into bite-sized pieces if you like.
Portion the rice into 4 bowls. Divide the black beans among the bowls. Top rice and beans with grilled sweet potatoes, red peppers and extra cilantro leaves. Pit and peel the avocado, and then dice into chunks on top of the bowls. Finish all of the bowls with extra spicy cumin garlic drizzle and some more salt and pepper. Serve warm.