Fish is such a delicate protein, it easily becomes a mess on the grill. You want clean, oiled and hot grates. Once the fish is on, let it cook most of the way before trying to flip it and then only give it a minute on that other side before pulling it off. It’ll continue to cook through as it rests and for a fatty fish like salmon, it’s nice to have it cooked medium anyway.
I understand feta cheese is not Mexican but neither is salmon really. A real sheep's milk feta has more flavor for me than cotija, so I stay untraditional. Any extra sauce makes a great dip for sweet potato wedges or thinned out slightly as a salad dressing. —sproutedkitchen
Make a spice paste by mixing the olive oil, brown sugar, cumin, chili powder, coriander, salt and lime juice. Rub this into the flesh of the salmon and let it sit for at least 10 minutes. Meanwhile, make your blender sauce.
Into a food processor or blender, add the garlic and jalapeño (I like medium spice so I leave most seeds in, if you do not, remove the seeds from the jalapeño). Pulse a few times to chop. Add the lime juice, water, olive oil, cilantro, parsley and salt and pulse a few more times. Add your avocados and blend again until just smooth. Taste for seasoning. This is for a medium thick sauce, add lime juice or water to thin.
Oil the grates, put on your salmon. Cook until you can see on the edges it’s mostly cooked, about 5-8 minutes depending on thickness of the filet. Flip the fish and cook another 1-2 minutes on this side. Pull it while it feels slightly tender in the center, like the meaty part of your thumb. Remove to rest. After a few minutes, the fish should flake easily for tacos.
Warm the tortillas on the grill.
To assemble tacos, put a few ounces of flaked salmon on your tortilla. Top with some shredded cabbage, blender sauce, a sprinkle of feta and radish.