What aroused Yaakov's ire against Lavan?
Ramban, Seforno, Ohr ha'Chayim: Initially, Yaakov was concerned lest one of his wives or slaves had stolen the Terafim. But when Lavan found nothing, he concluded that Lavan's claim was merely a pretext to search Yaakov's belongings - because Lavan suspected him of stealing something of his. 1
Malbim: There are four reasons to chase after a hired hand [who fled]. (a) If the worker sinned against him - what was my intentional or Shogeg sin?! (b) If he stole from his house - what did you find from your house?! (c) If the worker took too much wages, or received too little. I did not eat your animals, and you never lost through me due to me miscarriages, Tereifah or theft! Surely you did not pursue me to give to me more wages - you swindled me to get an extra seven years for Rachel, and changed my wages 100 times in the last six years!
Oznayim la'Torah (citing Sefer ha'Carmel in the name of the Malbim): The Torah writes "va'Yichar le'Yaakov" and not "va'Yichar Apo," because it was not not with Lavan with whom Yaakov was angry, but with himself - in that he must have sinned for this to be happening to him. 2
Indeed, following Lavan's dishonest treatment, (refer to 31:39:1:1) Yaakov had every right to take whatever he could as compensation, as he goes on to tell Lavan in no uncertain terms.
Oznayim la'Torah: The Midrash Rabah makes the same observation, based on Yaakov's own words "Mah Pish'i u'Mah Chatasi?"
What does "Ki Dalakta Acharai" mean?
Tosfos ha'Shalem (to 31:35 (2)): It is like one who pursues, and his heart is burning (Dolek).
Tosfos ha'Shalem (4, citing R. Efrayim): You burned (pursued rapidly like fire) after me.
Why does it say "va'Ya'an Yaakov"? (The Torah usually says "va'Yomer" even when one responds.)
Tosfos ha'Shalem (2): Amidst anger, Yaakov raised his voice. "Oneh" connotes loudly - such as "v'Anu ha'Leviyim... Kol Ram" (Devarim 27:14).
What is "va'Yarev b'Lavan"?
Ohr ha'Chayim #1: Amidst anger, Yaakov quarreled with Lavan. If not for the anger, he would not have quarreled with him.
Ohr ha'Chayim #2: It is only because it was Lavan that it seemed like a quarrel. Had he said so to someone else, it would not be called a quarrel.
Ohr ha'Chayim #3: He quarreled with him alone, not in front of others.
Ha'amek Davar: Normally, it says va'Yarev Es or va'Yarev Im. Here, it says "b'Lavan," i.e. due to Lavan's actions (that he suspected Yaakov and accused him,) Yaakov was silent, amidst pain. Lavan then asked to make a Bris of Shalom. This is possible only after rebuke; this drew him to quarrel with Lavan.