Cut the tuna into large, even cubes and slice the bananas to match.
Wash the cherry tomatoes and arugula. Thread alternating tuna and banana pieces onto wooden skewers. Drizzle with juice from 1 lemon and 10 cl olive oil.
Mix the arugula, mash, dill, and chervil sprigs. Add the minced apples and dress with remaining olive oil and juice from the second lemon.
Sear the skewers briskly for 1-2 minutes per side over high heat, along with the rolled belly slices and cherry tomatoes.
Serve hot with the fresh salad mixture.
