In a small 2 cup measuring cup, or something similar size and shape, combine all the marinade ingredients.
Using an immersion blender, puree the marinade until smooth.
Transfer to a re-sealable plastic bag and add the steak, seal and shake to coat. Refrigerate the beef for 4 hours to tenderize and flavor the beef.
Prepare grill on med. high heat.
Drain the marinade from the beef. Lightly oil the grill. Season liberally with salt and freshly ground black pepper.
Grill the steak over medium-high heat and cook for 4 minutes on each side and then transfer to a cutting board and let rest.
Once the beef is off the grill and resting, add the bell peppers and onions tossed with lime juice and olive oil, to a cast iron skillet ( I put the skillet onto the grill to preheat while cooking the steaks). Grill the mixture for 7 to 8 minutes until the vegetables are just barely limp.
When the peppers and onions are done cooking, remove the skillet and heat up the tortillas.
Place tortillas on the grill and let it char about 30 seconds, flip the tortilla and repeat on the second side.
Once heated and charred remove the tortilla to a clean tea towel and wrap to keep warm.
Thinly slice the steak against the grain on a diagonal.
Spread some guacamole on a tortilla, top with a few slices of steak, peppers and onions, and salsa. Roll up the tortilla to enclose the filling.
May also be served with sour cream and shredded cheese.