Yes, you can adjust the spice level in this recipe according to your preference. If you prefer less spice, you can do a couple of things to reduce it. First, you can rinse your chipotles so that they don’t have the spicy adobo sauce on them and remove some of the seeds which also add spice. You could also reduce the amount of chipotles in adobo sauce used in the recipe or skip them altogether, though that will also change the flavor to a degree. On the other hand, if you like your Tacos Al Pastor spicier, you can increase the amount of chipotles in adobo by ½ or 1 can or add 2-3 Tablespoons of hot sauce to the sauce mixture. You could also add some crushed red pepper, cayenne pepper or chili powder to the seasoning mix for added spice. You could also decrease the amount of pineapple added which will lower the sweet level and allow the spice to be higher. Keep in mind that the recipe as written has a medium level of spice, so adjust accordingly to your taste.