Pre-heat an outdoor grill or grill pan to medium-high. Rub the steaks with oil, chili powder and steak seasoning. Grill the steaks, tented loosely with foil, turning once, for 15 minutes for medium-rare doneness. Remove from the heat and let rest.
Combine the sauce ingredients in a blender or food processor and puree until almost smooth.
Lightly spray the tortillas with cooking spray and char for a few seconds on each side on the grill or stovetop.
To form each slider, spread some sauce on each tortilla, top with very thinly sliced steak in an even layer and fold the tortilla into quarters.