Preheat the oven to 425°F (220°C).
In a large bowl, toss the diced sweet potatoes with olive oil, 1/2 teaspoon salt, and 1/4 teaspoon black pepper until evenly coated.
Spread the sweet potatoes in a single layer on a baking sheet lined with parchment paper.
Roast the sweet potatoes in the preheated oven for 20-25 minutes, turning halfway through, until tender and lightly browned.
While the sweet potatoes roast, heat a large skillet over medium-high heat.
Add the ground beef to the skillet and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Add the chopped onion and minced garlic to the skillet with the beef and cook for another 3-4 minutes until the onion is softened.
Stir in the ground cumin, smoked paprika, chili powder, 1/4 teaspoon black pepper, and 1/2 teaspoon salt. Cook for 1-2 minutes until fragrant.
Remove the skillet from heat and set aside.
In a small bowl, combine the Greek yogurt, fresh lime juice, and 1/4 teaspoon salt. Stir well and set aside.
To assemble the bowls, divide the cooked quinoa evenly among four bowls.
Top each bowl with roasted sweet potatoes, the spiced ground beef mixture, fresh baby spinach, and diced red bell pepper.
Drizzle each bowl with the lime yogurt sauce and sprinkle with chopped fresh cilantro.
Serve immediately and enjoy!