In a one gallon soup pot, heat oil over a low medium flame. Add onion and salt. Sweat until the onion softens to a buttery texture, about 7 min.
Add the Cauliflower and Roasted Tomatoes, saute over medium flame for 5 min.
Add Curry Paste and saute until fragrant for about 1-3 min.
Add stock and raise heat to bring to a boil. Once boiling reduce heat to a simmer and allow to cook partially covered for 25 min.
Puree Soup in a blender with Coconut Milk until very smooth.
Return the soup to the pot, reheat, stir in Rice Vinegar, and adjust seasonings with salt and pepper.