Teriyaki Tuna Pressed Sushi with French Bean Strips

200g / 7 oz sushi-grade tuna or tuna fillet, thinly sliced
2 tbsp teriyaki sauce
1 tbsp oil
10 French beans, trimmed and cut in half oil, for cooking
1 tsp toasted sesame seeds
2 tbsp Japanese mayonnaise
pickled ginger and wasabi paste, to serve

To the sushi rice
125g / 4 1/2 oz sushi rice, washed under cold running water until the
water runs clear, then drained
160ml / 5 1/2 fl oz water
1/2 piece of kombu
1 tbsp sushi rice seasoning

Put the sushi rice in a saucepan with the water and kombu, cover and bring rapidly to the boil. Remove the kombu, then re-cover, reduce the heat and simmer for 10 minutes. Turn off the heat and let the rice stand, covered, for 15 minutes. Put the hot rice in a large, very shallow bowl, pour the seasoning evenly over the surface, and mix it carefully into the rice with a spatula, using quick cutting strokes. Fan the rice with your hand to cool it.

Coat the tuna slices in the teriyaki sauce and cook in the oil in a frying pan for 1 minute on each side, then cut into thick strips. Blanch the French beans in boiling water for a minute, then cool under cold running water and drain.

Oil an 18cm / 7in loose-based square cake tin and line it with a piece of cling film large enough to hang over the edges. Oil the cling film and sprinkle in the sesame seeds. Pack the rice into the tin, spread over the mayonnaise, then arrange the tuna and beans in thick, diagonal strips. Cover with cling film, then put another tin on top and weigh down.

Chill for 15 minutes, then loosen the sides of the tin, and pull out the sushi. Cut into 15 pieces with a wet, sharp knife. Serve with pickled ginger and wasabi paste.