How does an uncircumcised person cleanse himself if urine remains between the foreskin and the penis after wiping? And is wiping three times sufficient, even if some urine remains?

Circumcision is obligatory for males. Some of the predecessors emphasized it greatly. If you are not circumcised, you must hasten to get circumcised, especially if you suffer from a problem in purifying yourself completely.

However, if circumcision would cause you harm, or if your doctor advised you to delay it, then there is no blame upon you for that. In this case, you must purify the area from impurity as much as possible and perform ablution for every prayer. You can use a tissue or cloth to prevent the spread of impurity, while purifying the area before each prayer until you are able to get circumcised.