For the rub, place all ingredients in the bowl of a food processor and process to make a paste. Place the chicken in a bowl and spread the paste under the skin of each thigh. Marinate for at least an hour, or up to 3 hours.
Preheat the BBQ or oven grill. BBQ the chicken, turning for 10-15 minutes, or grill under a hot heat, turning for 10-15 minutes. Remove from heat and place in a bowl to cool slightly before cutting into bite size pieces.
For the warm salsa, place the oil in a frying pan over high heat. Add the onions and capsicum and cook, stirring occasionally for 2-3 minutes, reduce heat and cook a further 5 minutes until the mixture is soft and starting to caramelize. Add the cumin and tomatoes and continue to cook over a low heat for another 10 minutes, stirring, until the tomatoes are soft. Season to taste with salt and black pepper.
To serve, place the warm tortilla on a plate, spoon over the crème fraiche and guacamole and top with chicken, salsa and a good smattering of the remaining ingredients.