For the tempura batter, whisk all ingredients together with a wand until smooth.
Clean the spring leeks, remove the dark green, score them in strips at the top and place them in cold water.
Turn the vegetables, king prawns and salmon cubes in flour to the other side, pull them through the tempura batter and bake in turn in hot fat until crispy.
Drain on a kitchen towel, season with salt and bring to the table with the Sweet Chili Sauce.