Method:
Combine jicama, tomato, jalapeño, cilantro, lime juice and 1/4 teaspoon salt in a small bowl. Set aside.
Sprinkle steak with chili powder and remaining 1/2 teaspoon salt. Heat a large cast-iron skillet over high heat. When very hot, but not smoking, add 2 teaspoons canola oil and then the steak. Cook until well browned, 2 to 3 minutes per side. Transfer to a cutting board and set aside. Return the skillet to high heat and add remaining 2 teaspoons canola oil, onion, bell peppers and garlic. Cook, stirring, 2 minutes. Lower heat to medium, cover skillet, and cook, stirring occasionally, until vegetables are tender, about 8 minutes.
Slice the steak thinly against the grain. Remove the skillet from the heat, push vegetables to one side, and place steak slices on other side. Pass jicama salsa and warm tortillas and let guests roll the steak and vegetables in the tortillas and top with salsa.