In a small bowl, whisk together marinade ingredients. Place steak in a shallow container, and pour marinade over it. Refrigerate, covered, 8 hours or overnight to tenderize meat.
Drain the marinade from the meat. Grill the steak in a ridged grill pan over medium-high heat for 4 minutes each side. Transfer the steak to a cutting board and let stand.
In the same pan with the steak juices, add the bell peppers and onions. Saute the mixture for 3 minutes until the vegetables are limp. 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 fresca. Roll up the tortilla to enclose the filling.
May also serve with sour cream and shredded cheese.
Recipe courtesy of Tyler Florence