Heat the vegetable oil in a large saucepan. Add the ginger, garlic and bell pepper and cook over moderate heat, stirring, until fragrant, about 2 minutes. Add the vegetable stock and bring to a boil. Add the shiitakes, cover and simmer over low heat until tender and the stock is flavorful, about 25 minutes.
Remove the shiitakes from the soup. Discard the stems and thinly slice the caps. Return the caps to the soup and add the cauliflower, zucchini and pickled vegetables, but not the Scotch bonnet. Simmer the soup over moderate heat until the cauliflower is al dente and the zucchini is just tender, about 4 minutes.
Whisk the tomato paste into the soup, then add the cherry tomatoes and the soy sauce. Raise the heat to moderately high, stir in the dissolved cornstarch and simmer, stirring, until the soup thickens, about 1 minute. Add the tofu, Scotch bonnet and pickling liquid and season with salt and pepper. Ladle the soup into bowls and garnish each serving with a few drops of sesame oil and some cilantro leaves; serve hot.