Heat a grill to medium high.
For the Bobby's rub for beef and pork: Combine the ancho chile, coriander, mustard, paprika, black pepper, salt, chile de arbol, cumin and oregano in a bowl. Set aside 2 tablespoons for the mushrooms. (Store the remaining spice rub, tightly covered, in a cool, dry place for up to 6 months.)
For the portobello mushrooms and rajas: Brush the mushrooms generously with canola oil and season the gill sides with the reserved 2 tablespoons spice rub. Brush the Anaheim chile and bell peppers with canola oil and season with salt and pepper. Put the mushrooms spice-side down on the grill. Put the peppers on the grill and cover the grill. Grill the mushrooms, turning once, until a knife inserted in the thickest part meets no resistance, 4 to 5 minutes per side. Transfer to a cutting board and tent with foil to keep warm. Grill the Anaheim chile and bell peppers, turning, until charred on all sides, 10 to 15 minutes (the Anaheim will take a few minutes less than the bell peppers). Transfer the peppers and chile to a bowl, cover tightly with plastic wrap and let rest 10 minutes.
For the tortillas and toppings: While the peppers rest, warm the tortillas on the grill a few seconds on each side; keep warm.
Remove the skins and seeds from the bell peppers and chile. Thinly slice the peppers, chile and mushrooms and combine in a bowl. Add the cilantro, olive oil, scallions, Fresno chiles, lime juice and salt and pepper.
Fill the tortillas with the vegetable mixture and top with queso fresco and a squeeze of lime.
Recipe courtesy of Bobby Flay