does mpaka here have a prefix or is the word always "mpaka"?
Very good question! When "mpaka" is a noun (border) then the plural is "mipaka". ;)
From Wiktionary: https://en.wiktionary.org/wiki/mpaka
At first glance, I thought this was going to say "I will eat a cat (paka)..." lol
Interesting that the "I die" part also has to be in the future tense.
Does it necessarily have to be future, or would having it in the present tense change the meaning?
Is this an idiom for I am very hungry like the English "I could eat a horse"?
more like hyperbole, but yes