1 1/2lbsflank or skirt steak, trimmed of fat and sliced into 6-inch long pieces
6Tbspfresh lime juice
3clovesgarlic, minced (1 heaping tbsp)
1jalapeno, seeded, stemmed and minced
2tspchili powder(preferably 1 tsp ancho chili powder and 1 tsp regular chili powder)
1 1/2tspground cumin
Salt and freshly ground black pepper
1/2cupfresh cilantro, left whole
2 - 3bell peppers sliced into 1/2-inch thick strips(2 for lesser amount of beef and 3 for greater)
1large yellow onion, sliced into 3/4-inch thick strips
8 - 12tortillas flour or corn tortillas(8 for lesser amount of steak and 12 for greater)
Avocado slices or guacamole
Pico de gallo or salsa, sour cream, shredded Monterey Jack cheese or crumbled Queso Fresco (optional)
In a small mixing bowl combine lime juice, canola oil, garlic, jalapeño, chili powder, cumin, paprika and season with salt and pepper to taste (I recommend about 1 1/2 tsp salt and 1 tsp pepper). Set aside 3 Tbsp of the marinade in refrigerator for the veggies.
Place steak in a gallon size resealable bag, pour in marinade and add cilantro, working to get some of the cilantro on both sides of each piece of beef. Seal bag while pressing air out, then rub marinade into beef. Chill 3 - 6 hours.
Preheat a grill over moderately high heat for about 15 minutes. Brush grill lightly with oil (it works well to soak a paper towel with oil then use long handles tongs to brush grates), remove steaks from marinade and place on grill, grill about 3 - 4 minutes per side to reach desired doneness (an instant read thermometer should read 120 in center for medium-rare and 130 for medium). Remove from grill and transfer to a cutting board and tent with foil, rest 5 - 10 minutes while grilling veggies, then thinly slice against grain.
Meanwhile, toss veggies with remaining 3 tbsp marinade, season with additional salt as desired, add veggies to grill (the length of veggies should run opposite direction of grill grates so they don't fall in between. Place onions in hotter parts of grill so they'll finish the same time as peppers) and grill about 5 - 10 minutes until crisp tender. Transfer to a boil and cover with foil while assembling fajitas.
To warm tortillas you can wrap them tightly in two batches in two separate sheets foil and grill with veggies during last 2- 3 minutes, rotating once halfway through. Or you can place them in damp paper towels in microwave and heat until warmed.
To assemble, top warm tortillas with warm beef, veggies and desired toppings. Serve with lime wedges for spritzing over top.