First, a caveat: Since the wetness of okara varies from batch to batch and person to person, this recipe might require some tweaking. However, it shouldn't be tricky tweaking. If the okara is wetter than the masa mixture, then more masa flour will have to be added to compensate. If the okara is dryer, then more water will need to be incorporated into the mixture. This shouldn't be a huge pain -- at least it wasn't for me!
The tortillas that resulted from my first tortilla-centered okara experiment tasted great -- just like a corn tortilla should. I couldn't detect any weird aftertaste, and when I folded one of the tortillas around some leftover refried black beans, it made for a great snack. Here's the recipe that worked for me, with the okara I had on hand. It yielded 13 tortillas.
Mix in a bowl
1 cup + 3 Tablespoons masa harina de mais (instant masa flour)
2/3 cup water
1/8 tsp. salt
Stir with a spoon until ingredients are well incorporated.
1/4 cup okara
Incorporate okara into the masa mixture.
At this point, you'll need to assess whether or not the mixture is good to go, or if you'll need to add more water or more masa flour. One way to test this is to go ahead and try to make a tortilla.
I use a tortilla press to make tortillas, though you could also try using a rolling pin or even the palms of your hand. To use a tortilla press, you'll need a sheet of plastic to line the press. Take a golf-ball-sized piece of masa and roll it between your palms; place it in the middle of the press on top of the plastic. Fold the plastic over the top of the ball of masa, and flatten the dough in the press. Open the press back up, and carefully remove tortilla from the plastic. (This page has some good photographs of the process.)
If it falls apart, then you might want to try adding water, one Tablespoon at a time. If it sticks to your rolling pin or tortilla press, you might want to try adding more flour, also one Tablespoon at a time. Be sure you reincorporate your failed tortilla back into the mixture.
But once you have an uncooked tortilla that doesn't fall apart or stick to the plastic, slap that puppy down on a hot grill or pan. (I use a non-stick pan.) Cook at medium-high heat for a minute or so; flip over and cook for another 30 seconds or so. Feel your tortilla -- is it nice and flexible? Or does it crack when you try to bend it? If it's not flexible enough to fold over your hand, then you should try cooking the tortillas for a shorter period of time. An overcooked tortilla that cracks when you try to make a taco with it is no fun.
Store in a specialized tortilla holder or in a resealable plastic bag. Eat them within a day or two or freeze them. Use them for tacos, taquitos, tostadas, enchiladas, tortilla soup, fry them up to make chips, whatever.