Heat the oven to 175°C (350°F).
Cut out 16 tortilla flowers with the flower cutter.
Press the flowers into the mini muffin tin and flatten the petals along the top of the tin.
Brush the tortilla flowers with olive oil and sprinkle with sea salt.
Bake for 3-5 minutes, until slightly golden.
Allow to cool.
Mix the tuna, Greek yogurt, one tablespoon of sour cream, chives, red onion, lemon juice, onion powder, garlic powder, and sriracha. Add sea salt and pepper to taste.
Blend half an avocado, one tablespoon of sour cream, and a squeeze of lime juice in a mini food processor (or mix by hand) until creamy and smooth. Add sea salt and pepper to taste.
Use the round cookie cutter to cut out mango discs. The slices should be thin (about 3mm), so halve the discs if necessary.
Assemble the flowers: use a flat knife to spread the avocado cream on each tortilla petal. Spoon the tuna salad in the middle of the flowers and top with a mango disc.
Serve.