Preheat your grill to medium-high heat (around 400°F)

In a large bowl, toss sweet potato rounds with 2 tablespoons olive oil, salt, and pepper until evenly coated

Place the rounds on the grill and cook for 4-5 minutes per side, or until grill marks appear and potatoes are tender when pierced with a fork

While the potatoes are grilling, combine minced garlic, remaining olive oil, lime juice, and red pepper flakes in a small bowl

Transfer grilled potatoes to a serving plate and drizzle with the garlic-lime mixture

Sprinkle generously with fresh cilantro before serving