Preheat the oven to 400 degrees F (200 degrees C). Line a large baking sheet with parchment paper. Place wings on the baking sheet and sprinkle with 1/2 teaspoon salt.
Bake in the preheated oven for 15 minutes. Using tongs, flip the wings over and sprinkle remaining salt over the top. Bake for 15 minutes more.
Meanwhile, bring water, vinegar, sweet chili sauce, and Sriracha to a boil in a medium saucepan. Reduce heat and simmer until sauce thickens, about 5 minutes.
Transfer wings to a large bowl and pour sauce over the top. Toss to coat.
Set an oven rack about 6 inches from the heat source and turn broiler on high. Place a wire cooling rack on the baking sheet and arrange wings on top.
Broil wings for until crispy, about 5 minutes. Garnish with chopped green onion.