Prepare the grill (indoor or out) or the broiler.
Pound the chicken breasts to 3/4 inch thickness, and set aside.
Heat a heavy skillet over high heat for 3- 4 minutes.
Pour the wine into the skillet, and boil it for 1- 2 minutes to evaporate the alcohol.
Reduce heat to medium.
Stir in soy sauce, garlic, and pepper, and cook until they are just combined, about 1 minute.
Add butter and stir until just melted.
Remove skillet from heat.
Dip the chicken breasts into the sauce, and turn them to coat thoroughly.
Place breasts 3- 4" from heat source, or on in-door grill.
Cook a few minutes until done to your taste.
Remove from the heat and let it sit for about 5 minutes.
Slice the breasts into slim finger length strips.
To assemble the fajitas, pile a platter high with the chicken strips, and accompany the platter with tortillas, onion, pico de gallo, guacamole, tomatoes and bell pepper rings.
Let everyone help themselves.
For each serving, fill a tortilla with some of the chicken and portions of the garnishes.
Marinated onions: Reduce the stock to 1 cup in a small sauce pan.
Add soy sauce and chiles; stir.
Place onions in a medium bowl and pour the marinade over them.
Cover the bowl and refrigerate it for several hours or overnight.
Present the onions cold as a garnish, or heat them in the top of a double boiler and serve warm.
They'll keep at least 10 days.