In einem kleinenTopf ausreichend gesalzenes Wasser für die Süßkartoffel zum Kochen bringen. Die Süßkartoffel schälen, längs halbieren und in grobe Stücke schneiden, dann in das kochende Wasser geben und in 10–15Min. gar kochen. Tipp: Die Süßkartoffeln sind durch, wenn sie sich bei der Messerprobe leicht vom Messer lösen.
Den Fisch trocken tupfen und in ca. 1cm große Würfel schneiden. cubes of about 1cm squares. Fill the sesame seeds into a bowl and coat the fish cubes on all sides with the seeds. Slice the spring onion thinly on an angle and reserve some of the green part for garnishing. For the glazing sauce, mix ½ of the garlic and ginger paste with the sesame oil, the soy sauce and ½ of the spice mix.
Heat up a medium-sized pan on medium-high heat and add ½Tbsp of olive oil. When the oil is hot, fry the tuna cubes for ca. 2min., shaking the pan to turn them regularly. Add the spring onion slices to the pan and fry for 1min. Then turn the heat to low and deglaze the pan with the sauce, reducing it for ca. 30sec.
Reserve some of the cooking water in a cup, then drain the sweet potatoes into a sieve. Return to the pot and mash to a creamy mash, adding cooking water as needed. Tip: If you like, you can also add a little butter or oil. Season with a pinch of salt.
Halve the avocado, remove the pit and score the flesh crosswise. Use a spoon to scoop the avocado cubes out of the skin. Zest and juice one lime half and cut the other half into wedges.
Mix the avocado cubes with the lime zest and juice in a bowl. Season with a pinch of salt. Spread the sweet potato mash onto plates and top it with the marinated avocado cubes, the fried tuna tartare and finally ½ of the seaweed caviar. Sprinkle with the reserved spring onion greens and serve with the lime wedges.