Jetboil makes a fry pan that you can use with your PCS. You can find them at various outdoor stores that carry Jetboil products or online at various places. I have heated tortillas on it as well as cooked soup and made scrambled eggs and bacon.
Not sure how the jetboil works? You could go to a local machine shop and have them cut you a round piece of aluminum and finish the edges that would just sit on top of the stove. Would weigh next to nothing and take up almost zero room in a pack.
I am not too familiar with jet boil, other than they exist and are supposed to be the heat. What I would do is take your new pan,and while you are boiling water for the remainder of the wrap, set the pan on top of the jetboil cup as a sort of lid. Your water will boil, and you will heat the pan enough to heat the tortilla. My dad would just fire up a gas burner and lay the tortilla across it for 2-3 seconds, flip the tortilla, and repeat until it was hot. You can also just use coals directly, if you have a fire. Another option previously mentioned is to make your breakfast burritos at home and wrap them first in wax or parchment paper (I much prefer parchment) then in a double layer of heavy duty aluminum foil. then freeze, and put in your pack. You could likely wrap your sleeping bag or other insulators around them to keep them cold longer. A dry bag dunked in a running stream would work for this too. Where I hunted last year, night time temps were below 40, so the food could be just hung up in a mesh bag near camp. This violates many food safety rules, but I am not generally bugged by food borne illness. I bet frozen burritos, properly wrapped, would stay frozen 24 hours or so in your pack, then stay below 45 degrees F or so for 2-3 more days depending on your setup and the ambient air temp, and how your store your stuff at night.
This is cheaper, and arguably faster on the trail, and you have total control over what is in your food. To warm it up, you could jam the wrapped burrito into the coals from the previous night's fire, but then again I like fires in the evening. You could also wake up in the morning, put a hot hands warmer in your jacket pocket with the burrito next to it. Still another way to warm it would be to boil your water for coffee as normal, and but the wrapped burrito in a freezer bag and drop it into the mug. The water will take longer to boil, but it will be doing double duty. When your burrito gets hot, remove, and add your coffee to the mug, let is steep. As you strike camp you will be warming breakfast, you can brew up a cup of coffee, and by the time you are ready to leave your drink and burrito are hot.