Pick the coriander leaves, discarding the stems. Combine the sweet chilli sauce (see Kitchen notes), 2 tsp soy sauce and 1 tbs water in a bowl. Combine 2 tbs mayonnaise and 1 tsp water in a separate bowl.
Step 2 — Make coconut sambal
Put the coconut and ½ tsp chilli flakes, if using, in a cold large frypan over medium heat. Toast, tossing, for 2-3 mins until evenly golden. Transfer to a bowl. Add 2 tsp white vinegar, season with salt and pepper and stir to combine. Wipe the pan clean.
Step 3 — Cook chicken
Heat a generous drizzle of vegetable oil in the same pan over medium-high heat. Cook the chicken for 2-3 mins each side until browned. Add the sweet chilli sauce mixture and cook, turning, for 2 mins or until the chicken is cooked through and the sauce is thickened. Transfer to a plate. Taste, then season with salt and pepper.
Step 4 — Warm tortillas
Put the tortillas on a plate, slightly overlapping, and microwave for 30 secs or until warmed through (see Kitchen notes).
Step 5 — Serve up
Coarsely shred the chicken with two forks. Divide the tortillas among plates and top with the spinach, chicken and coriander. Drizzle with the mayonnaise and scatter over the coconut sambal. Enjoy!
Step 6 — Kitchen notes
Sweet chilli sauce isn't very hot, but if serving this to kids, you might like to leave their portion of chicken plain, or just drizzle it with soy sauce. ~ Don't have a microwave? Heat a large frypan over medium-high heat. Warm the tortillas, in batches, for 30 secs each side or until heated through.