Preheat an outdoor grill or grill pan to medium-high. Rub the steaks with oil, the chile powder and steak seasoning. Grill the steaks, tented loosely with foil, turning once, for 15 minutes for medium-rare. 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.