When we have fajitas I never use a "shop bought" - for want of a better explanation - to dry rub/marinade the meat. I bung a mixture of spices and crushed garlic (typical is cumin, smoked paprika and a wee bit cayenne pepper)that can vary depending on what I have in at the time in a bag, slop in some oil and lemon or lime juice and then add the meat, chicken or fish.
While the mixture is doing it's stuff I make a pico de gallo (it's a salsa but not cooked). Basically it's tomato, red and or white onion, chilli pepper, lime or lemon juice, coriander and salt. Everything is chopped up and mixed together. I also add some cumin, garlic and spring onions and sometimes a dash of hot pepper sauce. I don't have an exact recipe, but is something I tasted many years ago when I first had fajitas and I have invented my own mix over the years. I'm sure everyone who makes pico de gallo will have their own recipe or if they are really lucky a family recipe.
I think pico de gallo is a bit like home made soup - everyone has their own secret recipe!
We have fajitas with onions and peppers that are cooked but still have a wee bite in them and are slightly caught or charred at the edges, sour cream, pico de gallo and sometimes I make guacamole but not everyone in my family likes it.