Place cucumber in a blender or food processor: cover & process until smooth.
Place 3/4 cup puree in a saucepan (discard remaining puree or save for another use).
Add sour cream, water, sugar & salt to saucepan: heat to 120 degrees - 130 degrees (mixture will appear separated).
In a mixing bowl, combine 1-1/4 cups flour, yeast, chives & dill.
Add cucumber mixture & beat on low speed just until moistened: then beat on high for 3 minutes.
Add enough remaining flour to form a stiff dough.
Turn onto a floured surface: knead until smooth & elastic about 6-8 minutes.
Place in greased bowl, turning once to grease top.
Cover & let rise in a warm place until doubled, about 1 hour.
Punch dough down: let rest 10 minutes.
Shape into 12 balls: place in a greased 13-in. x 9-in. x 2-in baking pan.
Cover & let rise until doubled, about 45 minutes.
Bake at 375 degrees for 30-35 minutes or until golden brown.
Remove from pan & cool on a wire rack for 10 minutes. Serve warm.