Recipes: Grilled sweet potatoes with lemon herb sauce

Preparation:        Preparation time: 10 mins Cooking time: 10 mins Serving: 6 Ingredients: 1/2 small red onion, finely chopped 2 tsp. grated lemon zest plus 1/4 cup juice 2 lb. sweet potatoes, well-scrubbed and sliced into 1/4-in.-thick rounds 3 tbsp. olive oil, divided, plus more for serving Kosher salt and pepper 1 small fresno chile, seeded and finely...