Whisk 1/4 cup oil, red wine vinegar, jalapeno pepper, oregano, garlic, seasoned salt and cumin together in a large bowl to make marinade.
Divide marinade between 2 bowls. Place chicken strips in 1 bowl. Place all the capsicum and onion in the second bowl. Marinate at room temperature for 30 minutes.
Heat 1 tablespoon oil in a wok over medium-high heat. Add capsicum-onion mixture; cook and stir until softened and blackened in spots, about 5 minutes. Transfer to a bowl.
Heat remaining 1 tablespoon oil in the same wok. Add chicken; cook and stir until no longer pink in the center, 5 to 10 minutes. Return capsicum-onion mixture to the wok; stir until heated through. Serve over flour tortillas.
Substitute 2 teaspoons dried oregano for the fresh oregano if desired.