Whisk together the extra-virgin olive oil, lime juice, cumin, garlic powder and salt in a small mixing bowl. Brush the marinade on both sides of the salmon fillets. Place in a basket flipper or fish basket.
Place the sliced peppers and red onion in a grilling tray. Brush with olive oil and sprinkle with a pinch of salt. Place the basket tray on the hot grill and cook, stirring occasionally, until you get good grill marks all over and the veggies have softened, anywhere from 15 to 20 minutes. Meanwhile, place the basket flipper on the grill; grill the salmon until nicely browned on both sides and opaque in the middle, 4 minutes per side. Remove the salmon from the grill and transfer to a plate. Flake gently.
Place the tortillas on the grill for a few seconds per side, letting them char and bubble up.
Stuff each tortilla with a mix of peppers, onion and flaked salmon. Top with crumbled queso fresco, cubed avocado, cilantro and a final spritz of lime juice! Dive in.