Add mayonnaise, lime juice, sliced green onion, minced jalapeño (if using), chopped cilantro, ground cumin, smoked paprika, salt, and black pepper to the bowl.

Stir gently until ingredients are evenly combined but tuna retains some texture. Taste and adjust seasoning — add more lime or salt if needed. Cover and refrigerate while you prepare slaw and pickled onions (at least 10 minutes to meld flavors).

Slaw & Pickles

Quick pickled red onion

Place thinly sliced red onion in a small heatproof bowl. Stir together hot water, white vinegar, 0.25 tsp salt and 0.5 tsp sugar until dissolved. Pour over onions, press down to submerge, and let sit at room temperature for 10–15 minutes while assembling other components. Drain before using.

Make the slaw

In a medium bowl combine shredded red cabbage and grated carrot. Add 1 tbsp fresh lime juice, 1 tsp apple cider vinegar, 1 tsp olive oil, 0.25 tsp salt and 0.25 tsp sugar (if using). Toss until evenly coated. Refrigerate until ready to assemble.

Tortillas & Finishes

Warm tortillas

Warm tortillas one at a time in a dry skillet over medium heat for about 20–30 seconds per side, or brush lightly with olive oil/butter and warm until pliable and slightly golden. Keep warm wrapped in a clean towel.

Assemble tacos: place 2–3 tablespoons of the tuna mixture in the center of each warm tortilla. Top with a small handful of cabbage-carrot slaw, a few slices of quick-pickled red onion, and 2–3 avocado slices. Add cilantro leaves and a squeeze of lime. Finish with hot sauce or salsa if desired.

Serve immediately with lime wedges alongside. Leftover tuna mixture keeps covered in the refrigerator for up to 2 days; slaw is best same day.