Toast the cumin, red pepper flakes, and peppercorns in a dry skillet over medium heat for 3-4 minutes until they are very fragrant.
Grind the toasted spices.
Stir together all the spices in a bowl. Store in an airtight bag or container for many months.
Start with 1 1/2 tablespoons of seasoning per pound of chicken, beef, or veggie for tacos. Add the seasoning as the stuff cooks. Adjust according to your liking.