To make the corn paste, Blend together ½ cup corn kernels and ¼ cup water into a smooth paste. Set it aside.
Set the Instant Pot in saute mode and add oil.
Add onion, celery, ginger, garlic, and spring onion. Saute for one minute.
Add corn kernels, carrots, green beans, and salt.
Add vegetable stock and water. Mix well.
Set the Instant Pot to pressure cook mode for 3 minutes.
Do a natural release of pressure for 10 minutes, then do a quick release.
Meanwhile, make the cornstarch slurry. Combine cornstarch and water in a small bowl and mix well making sure there are no lumps.
Put the Instant Pot back to saute mode.
Add the slurry to the IP and mix well.
Add vinegar, soy sauce, chili sauce, and pepper.
Mix well and let the IP be in saute mode for 3 minutes.
Garnish with green onions and serve.