Preheat the oven to 425°F (220°C).
In a large bowl, toss the diced sweet potatoes with olive oil, smoked paprika, ground cumin, garlic powder, 1/4 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 non-stick skillet over medium-high heat.
Add the ground beef to the skillet, breaking it apart with a spatula.
Cook the beef for 6-8 minutes until browned and cooked through, seasoning with the remaining 1/4 teaspoon salt and 1/4 teaspoon black pepper.
Drain any excess fat from the skillet and remove from heat.
In a small bowl, combine the Greek yogurt and fresh lime juice to make a tangy sauce; set aside.
To assemble the bowls, divide the cooked quinoa evenly among four serving bowls.
Top each bowl with roasted sweet potatoes, cooked ground beef, baby spinach leaves, cherry tomatoes, red onion, and chopped cilantro.
Drizzle each bowl with the lime yogurt sauce before serving.