Mash avocado in a bowl using a fork or potato masher.

Add Greek yogurt, lime juice, lime zest, and tequila to the mashed avocado.

Mix well to combine the ingredients.

Incorporate minced jalapeno, finely diced onion, salt, pepper, and minced cilantro into the avocado mixture.

Stir until all ingredients are evenly distributed and the guacamole is smooth.

Adjust seasonings to taste if desired.

Pour the finished guacamole into a serving bowl and set aside.

Preheat a grill pan to medium-high heat.

Drizzle both sides of the fish with olive oil and season with salt and pepper.

Grill the fish on each side until it becomes opaque, approximately 4 minutes per side.

Remove the grilled fish from the pan and flake it into large chunks using a fork.

Heat flour tortillas on the grill pan until blisters form.

To assemble the tacos, spread a dollop of guacamole onto each tortilla.

Add flaked fish on top of the guacamole.

Garnish with shredded lettuce and chopped tomatoes, or any other desired toppings.