Good Life Graduation Kanye West

gotta be 'cause I'm seasoned haters gimme them salty looks

The term "seasoned" referres to being a veteran or knowledgeable about rap. The salty looks refer to enviuos or jealous looks. People are jealous because of his experience.
The correlation between the two lines in this particular lyric extends beyond the simply being disliked for his success and long-standing presence in the industry and includes the act of seasoning foods with varying herbs, spices and, most commonly, salt.