I don't know who the parents of Susannah (Leighton) Ricker were. I wish I did; right now, it's one of my brick walls.
Since originally editing her profile to remove her parents (and posting the first message in this thread), I have softened things a bit, from "was not" the daughter of Thomas and Susannah (Chesley) Leighton to "was almost certainly not." Ephraim and Susannah Ricker recorded the births of their sons but not their daughters. In Master Tate's diary, when he lists the children of Ephraim and Susannah (whom he calls "Hannah"), their daughter Eleanor precedes their son Tobias, who was their first recorded child, born in 1759. That implies that Eleanor was born about 1757. The Susannah Leighton who was the daughter of Thomas and Susannah was born in 1742. To be the mother of a child born in 1757, she would have had to been married at 14 or 15. Those very early marriages did occur in the period, but they were very rare.
The birth date of Susannah, daughter of Thomas and Susannah, is also inconsistent with the age at death on her gravestone. Ages at death shown on gravestones should be taken with a large amount of salt, but it would be unusual for a woman's age to have been overstated by nine years.
In addition, the author of the Leighton genealogy looked at the question and could find no evidence that Susannah (Leighton) Ricker was the daughter of Thomas and Susannah.
I don't think that the Susannah Leighton who married Ephraim Ricker was also the spouse of a Joseph Tucker. She was Leighton at her marriage, and she died before Ephraim did.
Incidentally, the Ricker genealogy totally screws up the Ephraim Ricker family. See the Research Note on his profile for the details.