Does anyone know what the best exercises would be for fat around the knees, especially the inner knees?

Just plain overall exercise as the body takes fat from all over as fuel for energy. Not just from one spot.

However to help build muscle tone, you can do lunges, leg extensions/curls and leg presses (these last three would need access to a machine or bench with leg attachments) Or you can use weighted lunges with dumbbells and squats. Squats with barball hits the legs in all areas (quads, hamstrings, glutes) as well as the back, shoulders and arms. This is one of the three "Core" compound exercises as it hits about 60% percent of the body.

The other two are the Bench press and deadlift.