Tomorrow, I'll be at the table When company comes.
First of all, the speaker probably doesn't literally mean tomorrow.
This poem works mostly by extended metaphor, and the "tomorrow" here is really alluding to a future time when blacks and whites will be equal.
This equality is expressed through the speaker's assertion that he, too, will "be at the table" the next time they have a party.
Nobody'll dare Say to me,
These lines continue in the same vein as the previous three, wherein the speaker imagines a future in which he'll be treated with the same kind of respect with which white people treat each other.
In this case, the emphasis is even a little stronger – not only is he present at the table, but he will have some control over what people do and don't say to him (i.e., he will command respect).
"Eat in the kitchen," Then.
Ha. So no one will dare tell him to eat in the kitchen anymore. Progress!
And, if we're thinking metaphorically (and it's poetry, so we should be), we can expand this notion just like we expanded the passage about "tomorrow."
Being told to eat in the kitchen is, in this case, representative of the larger problem that's being tackled in this poem – that is, the problem of racial inequality and injustice.
Think also about how inequality manifests (fancy word for "makes real" or "makes known") itself in our everyday lives – it's usually in the form of an unbalanced power relation. Hughes makes this even more apparent by actually "quoting" the whites who have been in power here – it makes the inequality take the form of a direct command.
Want more on this subject? Of course you do. Hop on over to our "Quotes" section, and we'll talk about this tidbit even more.