Prepare charcoal grill or preheat propane grill. Zest lemons to make 1 tablespoon. Cut zest into small pieces and set aside. Peel lemons and cut into 1/2-inch slices. Sprinkle with salt and brush with some of the agave. Grill on both sides until lightly charred. Remove from grill and discard seeds; chop into small pieces. Place in a bowl and add lemon zest, agave, soy sauce and red pepper flakes. Stir to combine. Divide glaze into 2 bowls. One part will be used for the grilling glaze and the other will be used as a condiment for the sandwich.

In a large bowl combine all sausage ingredients and mix to combine. Shape into 6 1-inch sausages to fit the hoagie rolls. Grill for about 7-10 minutes or until done, turning as needed. During the last 2 minutes of grilling, brush glaze on sausages.

Combine mayonnaise with mustard and brush on the cut sides of the bread. Place on the grill for a few seconds to toast lightly. Assemble hoagies with lettuce, sausage and additional agave lemon glaze.