Heat two teaspoons of oil in a frying pan and cook the chicken for ten minutes over a medium heat until cooked through with no pink meat (take care as the marinade can catch). Remove from the pan and set aside.
While the chicken cooks, heat the noodles in the microwave following pack instructions. Stir together the lime juice, sweet chilli sauce and soy.
Wipe the pan with kitchen paper. Add one more teaspoon of oil, then stir-fry the asparagus over a high heat for three minutes until just tender. Add the garlic and cook briefly until golden. Return the chicken, plus the noodles and sauce and toss together. Scatter in the salad onions. Serve with a lime wedge and a drizzle more sweet chilli sauce, if you like.