A small TV could go on that wall or it can be setup for hanging utensils, aprons. shallow niches could be made for spices or oils (Maybe with little guards to keep the bigger items from falling out).
Can't give a lot of useful ideas without a full understanding of what they want in the apartment and how much they are willing to spend / tear out. One can only throw out ideas only you and the owners can figure out if they fit the project. Are the doors necessary? Most people don't have doors at the kitchen... Is one to the outside? Depending on preferences and what is over on the right I'd want to take out the whole wall and make that peninsula as wide as possible (32" wide passageway).
The kitchen is very small (in my frame of reference anyway) so efficient cabinets and the nicest, most utilitarian equipment are most important. Clever use of any spaces for storage or fixtures is also appreciated. Make exact measurements of the space and utilize them in the drawings, making allowances for clearances (drawer spaces and door swing). Measure well. How thick are those walls? ...The size of doors and appliances.
Show the dishwasher. show the upper cabinets in the plan in some way to make it clear there is open counter space below or not (I use dotted lines). Do the interior elevation drawings of all walls once the plan is well along and the major appliance spaces determined (not that it won't change). The elevations might help with ideas and cause you to rearrange the plan.
Other thoughts: Good electrical fixture design and lighting are also key. That wall pantry space on the right could include a counter height open area, if that's desired to get a bit more prep space, like a spot for the wine serving or coffee maker. Cabinet maker and equipment supplier will be big helpers for ideas in this small space. I'd be sure the cabinets ran to the ceiling with extra storage up high.