Heat the canola oil in a large non-stick frying pan over medium-high heat. Add the onion and salt and cook, stirring occassionally, 5 minutes or until the onion softens and just starts to get golden. Stir in the garlic and ginger and cook one minute.
Stir in the curry paste, cayenne (if using) and cinnamon, then add chicken and stir to coat. Cook three minutes, stirring occasionally, then stir in the tomatoes. Reduce heat to low, cover and cook five minutes.
Stir in the coconut milk. When the curry starts to simmer again, stir in peas and cook another three to five minutes or until everything is hot. Serve garnished with cilantro.
Best Health tip: I pretty much prefer full-fat coconut milk over light. It brings so much more flavour and a luscious texture to the dish. Sometimes the fat will separate away from the liquid in the can — don't worry, just add the can's contents to the curry and stir it in (or give the can a good shake before you open it).