With fork tines, score cucumber lengthwise.
Halve lengthwise (seed if using field cucumbers); slice thinly crosswise.
Place in 4-cup (1 L) glass jar.
In small saucepan, stir together lime juice, oil, vinegar, water, sugar, salt, pepper and hot pepper sauce; bring to boil, stirring.
Reduce heat and simmer for 2 minutes; pour over cucumber and mix well.
Add onion; stir well.
Cover with jar lid; refrigerate for 12 hours.
(Salad can be refrigerated for up to 2 days.)