About 1 hour before serving, whisk together all of the spices (the mixed onion through the salt) in a bowl. Add the shrimp to a large ziplock bag or baking dish, then toss with olive oil and lime juice. Coat the shrimp with the jerk seasoning then marinate for 30 minutes in the fridge.
While the shrimp is marinating, combine all the salsa ingredients in a bowl, seasoning with the salt. Toss well and let sit until ready to eat.
After 30 minutes, heat a large skillet over medium-high heat and add a teaspoon or two of olive oil. Add the shrimp (I did not add any remaining marinade that was in the bag) and cook until it is pink and opaque on both sides, about 4-5 minutes. Warm tortillas if desired, then assemble tacos (or even nachos!) with shrimp, salsa and crumble queso fresco cheese.