"Are you trying to kill me with your eyes?"
Translation:Snažíš se mě zabít očima?
The difference between the two verbs is... different. Both can be translated as "try", but "zkusit" is "to make an attempt", it has something to do with a trial/test - zkouška, experiment - pokus, or experience - zkušenost (all these words come from the same root), while "snažit se" is "to make an effort" - related to the word "snaha" (effort). To a Czech mind it actually makes little sense to use the same verb (try) for these very different things.
However, "zkusit" is perfective and thus it can't be used in the present tense. If you want to express this other meaning of "try" in this (present tense) sentence, you must use the imperfective form of the verb, which is "zkoušet":
"Zkoušíš mě zabít očima?"
Since "killing with one's eyes" is an impossible feat, it's actually fine to use "snažit se" (making a mock effort) as well as "zkoušet" (making a mock attempt) here.
Using the perfective form automatically creates the future tense: "Zkusíš mě zabít?" Will you try to kill me? (Again, this is not about making an effort, about wanting to or striving to kill me, but about an experimental attempt - trying it to see if you succeed or fail.)