To edit a table content:-
1. se16n

• type &sap_edit into the command input
• then execute and there is a delete /edit icon below the menu bar

2. se11

• double click the enty that you wish to change
• type /h into the command input also known as debugging mode
• press enter
• in the debugging mode change the variable code = EDIT
• then execute and now the field can be edited

tcode = SE11
1. Generate the new table maintenance.
2. Double click on the generated screen.
3. At the main attribute tab. Enlarge the width eg 181
4. The click on the layout.
5. From the layout make sure it is showing the element list.
6. Click change.
7. Enlarge too the fields length ie. 181

Goto transaction code
SWI1 -> get the WIID

Then transaction code
SE11 -> SWWWIHEAD
- DELETE the WIID entry
or
- WI STAT = COMPLETED
or 
- WI STAT = DELETED

This is great to kill them off from your freaking tray

This is how you create maintenance dialog for ztable.

Use tcode SE11, enter the table name click change. In the next screen, click Utitlies-->table maintenance generator.

Enter &NC& as the auth group.
Enter the function group to use (ex. Z_TABMAINT)

click One Step, enter '1' as the screen number. Click the create button.

Once generated, you can use it by going to SM30, enter table name and click maintain.

Source
http://forums.sdn.sap.com/thread.jspa?threadID=1087759