Pickle the onion
Place the sliced red onion in a small bowl.
Mix the vinegar, hot water, salt and honey until dissolved, then pour over the onion.
Toss and leave for at least 20–30 minutes while you make the chicken.
You can make this several hours ahead and refrigerate it.
Brown the chicken
Pat the chicken thighs dry and season lightly with salt and black pepper.
Heat the olive oil in a large frying pan over medium-high heat.
Brown the chicken for about 2–3 minutes per side. It doesn't need to be cooked through yet.
Remove and set aside.
Cook the onion
Reduce the heat to medium.
Add the sliced brown onion to the same pan and cook for 5–7 minutes, stirring occasionally, until softened and beginning to colour.
Add the garlic and cook for another 30 seconds.
Make the tinga sauce
Add the canned tomatoes, chipotle chillies, adobo sauce, oregano, cumin, smoked paprika and chicken stock.
Stir everything together and bring to a gentle simmer.
For a smoother tinga, you can blend the tomato mixture before returning it to the pan. I prefer leaving a little texture in the sauce.
Cook the chicken
Return the browned chicken and any resting juices to the sauce.
Cover loosely and simmer gently for around 15 minutes, turning the chicken once, until completely cooked and tender.
Shred
Remove the chicken and shred it using two forks.
Don't shred it too finely. I like having some larger pieces of chicken left in the tacos.
Return the shredded chicken to the pan.
Reduce
Simmer uncovered for another 5–10 minutes, stirring occasionally.
The finished tinga should be juicy and heavily coated in sauce, but not watery enough to immediately soak through the tortillas.
Add the lime juice.
Taste before adding more salt. If you want more heat, add another little spoonful of adobo sauce.
Warm the tortillas
Heat the tortillas in a dry frying pan for around 20–30 seconds per side, until warm and flexible.
Keep them wrapped in a clean tea towel while you finish the batch.
Build the tacos
Add chicken tinga to each warm tortilla.
Top with avocado, pickled red onion and fresh coriander.
Finish with a squeeze of lime immediately before eating.