make sure you define its id, and the id of the form if there is a form around it (and id for the table).
Then you can simply view the source to figure out how the richfaces table generates the ids.
If you have a from with the id myForm and inside that a table with the id aTable and on each row you have an inputText with the id myInput then I believe the generated ids are as follow:
Row 1 id = myForm:aTable:0:myInput
Row 2 id = myForm:aTable:1:myInput
Row 3 id = myForm:aTable:2:myInput
Row 4 id = myForm:aTable:3:myInput
Row 5 id = myForm:aTable:4:myInput