Fry or grill the chicken thighs. Cool and cut into 1cm strips. Do the same with any leftover roast chicken.
Slice the pepper and ginger into thin strips. Slice the spring onion diagonally. De-seed and finely chop the chilli.
Whisk the soy sauce, sugar, vinegar and both oils in a mixing bowl. Add the garlic and chilli.
Scatter the ginger, pepper and spring onion slices onto a serving plate, then drizzle with half of the dressing. Put the chicken slices on top and drizzle with the remaining sauce.
Serve at room temperature.