CUT peppers lengthwise in half. Remove and discard membranes and seeds.
MIX meat, rice, peas, and 1/4 cup each water and barbeque sauce just until blended; spoon into peppers.
COMBINE remaining water and barbeque sauce in slow cooker. Add peppers, filled sides up; top with VELVEETA.
COVER with lid. Cook on LOW 5 to 7 hours (or on HIGH 2-1/2 to 3-1/2 hours).
SERVE peppers topped with sauce.