Preheat oven to 350 degrees F. Spray 9X13 cookie sheet with non-stick cooking spray In a small bowl, mix garlic, lime juice,mayo and agave together with a whisk. Mix tuna, broccoli slaw, green onion, jalapenos, cilantro, black olives and salt together in a large, separate bowl. Pour mayonnaise mixture over broccoli coleslaw/tuna mixture and mix well. Toast bread (to prevent sogginess) Top toast with about 1/3 - 1/2 cup broccoli/tuna mixture (however much you can fit on) Soften taco shells in microwave for 20 seconds then crush. Spread crushed shells over tuna melts, dividing shells between all 4 melts Spread 1 tbsp of salsa on each melt over crushed taco shells. Top with both cheeses, dividing between all 4 melts, Melt in oven for 8 minutes, then turn up to broil for about 2 minutes or until cheese is bubbly and starting to brown. Top with additional salsa and sour cream as garnish, if desired.