1 Rinse asparagus, trim and cook in a pot of boiling salted water for 8 minutes. Rinse snow peas and cook in a pot of boiling salted water for 1-2 minutes. Rinse scallions, trim and cut into rings. Rinse oak leaf lettuce and arugula, spin dry and tear into bite size pieces. Mix lemon juice in a bowl with olive oil, salt and pepper. Finely grate lemon peel.
2 Roll tuna steaks in sesame seeds and gently press. Heat 3 tablespoons vegetable oil in a pan and fry steaks on each side for 1-4 minutes. Cut tuna steaks into thin slices (if desired). Rinse basil, shake dry and pluck leaves from the stems.
3 In a large bowl, mix lettuce, basil, asparagus, scallions, arugula, lemon zest and snow peas with oil and lemon sauce. Cover with tuna steaks. Serve on plates immediately and season to taste with salt and pepper.