For the spicy peanut vinaigrette:
1) Put the vinegar, soy sauce, ginger, garlic, peanut butter, chilli oil, honey and sesame oil in a blender and blend until smooth. With the motor running, slowly add the rapeseed oil until emulsified. If the vinaigrette is too thick, thin with a little warm water. Season, to taste, with salt and pepper.
For the salad:
1) Preheat griddle to high. Brush the radicchio with oil and season with salt and pepper, to taste.
2) Griddle until lightly golden brown.
3) Arrange radicchio, chicory and watercress on a platter and drizzle with the peanut vinaigrette. Garnish with peanuts, chives and coriander seeds.