Spicy Pork and Spinach Dumplings with Soy Dipping Sauce

Ingredients

• 1 tsp. plus 1 tbsp. vegetable oil, divided
• 1 c. baby spinach leaves
• 1/4 lb. ground pork
• 1 tsp. minced garlic
• 1 tsp. grated fresh ginger
• 1/2 tsp. red pepper flakes
• 1/4 tsp. cornstarch
• kosher salt
• Black pepper
• 1 tbsp. flour
• 28 dumpling or wonton wrappers
• 2 tbsp. soy sauce
• 2 tbsp. rice vinegar
• 1 tsp. sesame oil
• 2 green onions, thinly sliced (green parts only)