This is enough sauce to readily cover 300g meat (more than ample for 1 as a main meal).
Make the sauce in a medium saucepan by combining, 1 Tbsp tomato puree, 1 Tbsp tomato ketchup, 240ml orange juice, 3 Tbsp white wine vinegar, 1/4 tsp fine salt, and 2 Tbsp sugar. Add a roughly chopped onion, some red/orange pepper, and some pineapple chunks. Heat up and simmer for about 5 minutes. Thicken the sauce by stirring in a couple of tablespoons of cornflour/water mixture.
For your meat of choice, cut into bite size cubes (smaller means more crunch:chicken ratio), cover with whisked egg white and then transfer each to a bowl of cornflour to coat. Place into hot fat until done – this will be dependent on meat type and cube size. 2cm pork will be around 4/5 minutes. Chicken a bit less.
Combine just before serving so that the crunch is not lost.
Toss over some finely sliced red chilli.