Heat vegetable oil in a large pot over medium heat
Add onion, ginger and garlic, and cook for 2-3 minutes, stirring until fragrant and soft
Add the red curry paste and cook for a further minute
Mix in the chicken stock, coconut milk, caster sugar and fish sauce
Bring to a boil then reduce to simmer for 10 minutes
Add lime juice, taste and season as desired
Boil wontons and Asian greens separately
Transfer wontons and greens to serving bowls
Ladle over the hot soup
Garnish with fresh herbs, chopped chilli and fried shallots