Brush trout fillets with olive oil and season with salt, pepper, and chili flakes. Set aside.
For the coleslaw, mix the mayonnaise, chili powder, and lime juice together. Toss together with the cabbage and chill.
In another bowl, toss onions, vinegar, olive oil, and salt together and let sit for 10 minutes for onions to soften.
For the salsa, toss together cherry tomatoes, green onion, lime zest and juice, olive oil, garlic, chili, avocado, and salt and pepper to taste.
Heat grill or grill pan to medium-high heat. Place trout on the preheated grill, skin side down for two minutes. Turn and cook for two more minutes. Let the fillets cool briefly and then peel the skin off the trout.
Warm the corn tortillas briefly over the grill, divide the coleslaw and salsa between each tortilla.
Top with two slices of trout and garnish with pickled onion and lime wedges.
