Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Peel the sweet potato and dice into uniform 1/2-inch cubes to ensure even roasting.
Place the sweet potato cubes on the baking sheet, drizzle with olive oil, and sprinkle with a pinch of sea salt and black pepper.
In a medium mixing bowl, combine the ground turkey, garlic powder, dried oregano, and the remaining sea salt and black pepper.
Gently mix the turkey by hand and roll into approximately 12 small meatballs, about 1 inch in diameter.
Arrange the meatballs on the baking sheet alongside the sweet potatoes and roast for 20-22 minutes until the turkey is cooked through.
While the tray roasts, whisk together the lemon juice and tahini in a small bowl with a teaspoon of water to reach a drizzling consistency.
During the last 2 minutes of roasting, add the fresh spinach to the tray to lightly wilt it in the oven's residual heat.
Divide the wilted spinach, roasted sweet potatoes, and meatballs into a bowl and finish with the zesty tahini drizzle.