Cut the potatoes into bite-sized pieces and cook in salted water until soft (10-15 minutes). Also cut the beans into bite-sized pieces and cook for about 7 minutes. You can still have a bite.
Halve the cherry tomatoes. Chop the oregano and cut the basil into small pieces.
For the dressing:
Squeeze the lemon, mix the juice with the olive oil, the pressed garlic clove, mayonnaise, basil and oregano and season with salt and pepper.
Mix the potatoes, beans and tomatoes with the dressing.