Preheat your oven to 425°F. Toss the diced sweet potatoes with olive oil, cumin, chili powder, salt, and pepper in a large bowl until evenly coated. Spread them in a single layer on a baking sheet, making sure there's space between each cube for proper air circulation.

Roast the sweet potatoes for 25 to 30 minutes, flipping them halfway through with a spatula. You're looking for golden-brown edges and fork-tender centers.

While the sweet potatoes roast, cook your rice according to package directions (this typically takes 15-20 minutes for white rice, 40-45 for brown rice). Once done, fluff it gently with a fork and cover it to keep warm.

Prepare your toppings by slicing the red onion, halving the cherry tomatoes, draining the black beans and corn, and chopping the cilantro. Slice the avocado just before assembling to prevent browning.

Assemble your bowls by starting with a generous scoop of warm rice as the base. Arrange the roasted sweet potatoes, black beans, corn, red onion, cherry tomatoes, and avocado in sections over the rice. Finish with fresh cilantro and a generous squeeze of lime juice. Add hot sauce or salsa if desired.