Pork shoulder is fatty yet tender. Cooking it on high heat helps to get rid of some of the fat and caramelizes the delightful spices.
In a mortar and pestle, blend the cumin, herbs, chilies, salt and pepper. Use this blend to season the pork.
In a large, heavy pan, heat the oil on medium heat. Cook the pork for 3-4 minutes without turning over.
Turn over the pork and continue cooking until pink meat juices appear on the surface of the pork (2-3 min.)
Sprinkle the chopped garlic onto the slices of pork to lightly brown for aprox. 30 seconds. Add the lemon juice or vinegar. Shake the pan well and serve immediately.