Combine flour, baking powder, and salt into a large bowl. Add spoonfuls of the vegetable shortening, coating each dollop with the flour mixture, and cut in with a pastry cutter until mixture resembles course crumbs.
Divide the mix between two bowls if making both Salsa and Guacamole flavored tortillas. If you are making just one of the flavors, you will need to double the amount of flavoring mix.
Add the Salsa flavored mix to one bowl, and the Guacamole flavored mix to the other, or if using one flavor, add to the one bowl. Cut in the flavored mixes thoroughly.
Slowly pour in the water (1/2 cup per bowl, or one cup if using just one of the flavors), stirring to bring mixture together. Lightly kneed dough 30-40 times, or until it becomes a cohesive ball of dough and less sticky. Cover the bowl(s) with a dish towel and allow to rest for an hour.
Roll into golf ball size balls, place on a baking sheet or cutting board, cover with dish towel and let rest for 20 more minutes.
Heat a cast iron griddle or skillet to medium-high/high heat. One-by-one, roll out the balls of dough very thin, using additional dusting of flour to achieve desired results.
Place the tortilla on the griddle or skillet and cook each side for about 20-30 seconds. Remove to a plate while warm and slightly browned in spots. Stack and cover with a towel to keep warm.
Serve immediately, or cool to store in a container.
