Whisk together lime juice and zest, vinegar, red onion and jalapeno; let sit 5 minutes to quick-pickle. Whisk in oil and pour dressing over corn and blackberries. Stir gently and season with salt and pepper, to taste.
Preheat oven to 450°F. Line a baking sheet with aluminum foil.
Combine chili powder, cumin, oregano, salt and pepper. Lightly pat the salmon filets dry with paper towels. Then place them in a single layer on the baking sheet. Drizzle with oil and sprinkle with seasoning mixture. Bake until the internal temperature of the salmon reaches 145 degrees, about 8-10 minutes, or until it flakes easily with a fork and is opaque throughout. Once cooked, use a fork to shred salmon into large pieces.
Add the salmon to your tortillas, top with salsa and cilantro.
Make ahead: The relish can be made ahead and stored in the refrigerator for up to 2 days.